Failures are shown here to help identify the causes of failure, so that, where possible, preventative measures may be taken. (PSM-15 to PSM-55) The battery voltage of the absolute pulse coder is low. No matter which type of overload is used it must be a Class 10 overload or capable of providing Class 10 protection. LOAD TA CHOMETER. If the motor gets too hot, reduce the pinion size, increase the spur size, or reduce the pack voltage. The most common causes of overheating are; the use of a motor with the wrong characteristics, poor cooling from obstructed ventilation devices, persistent overloading, excessive friction, and electrical overloads. Motor Control and Protection Major Features and Benefits The SEL-710 Motor Protection Relay provides an exceptional combination of protection, monitoring, control, and communication in an industrial package. However, currents that flow through induction motor bearings can also create premature bearing failure. Besides that, a drive may also experience overcurrent trips or possibly a motor-related fault such as an overload. Servo Motor Troubleshooting Common Servo Motor Issues & Possible Causes. If tripped determine cause and correct problem. * Nominal overcurrent allowance for a 300 HP motor is 478 FLA @ 150% = 717 A allowed for one minute. Two things can cause dead spots. This will result in an overcurrent through the motor winding. I experienced similar problem of my MH55 Ingersoll Rand Compressor tripping off on MTR Overld. Gearing Always start with stock gearing. If too low the motor winding may be shorted. Negative sequence overcurrent relay and protection assemblies RXIIK 4 and RAIIK 400 nite time = 0-100 seconds. Negative Sequence Relay Definition: A relay which protects the electrical system from negative sequence component is called a negative sequence relay or unbalance phase relay. Overloads are also designed to protect the motor from extreme cases of overcurrent. Loss of Engine Oil 1. Loose connections or broken conductors frequently are culprits when overcurrent and control problems occur. *6 and *7 *8: Preliminary excitation ・Excitation is carried out to create the motor flux before starting the motor. For dsPIC DSC’s for PMSM Motor Control Start with the: 70MIPS dsPIC33EP64MC206; Microchip offers both MIPS and ARM Cortex MCU's for high performance, 32-bit motor control. Induction is the creation of an. Most of motor winding failure occurs due to overload. A relay that operates or picks up when its current exceeds a predetermined value (setting value) is called Over-current Relay. Cooling Fan Circuit Over Current. CoolAutomation is the industry leader in Internet of Climate (IoC) technologies. free to spin. only designed to protect the motor from overload or failure to start overcurrent. However, currents that flow through induction motor bearings can also create premature bearing failure. Motor protection circuit breaker (MPCB) Application-specific variations of the MCCB, these breakers combine the short-circuit and isolation functionality of the MCCB with the motor overcurrent protection of a traditional overload relay. Servo Motor Troubleshooting Common Servo Motor Issues & Possible Causes. Therefore the motor is receiving this current as well. Overload over current yields low magnitude current compared to short-circuit and ground-fault overcurrent. 14 Ring mains 9. 1 ‘51’ overcurrent protection 43 9. Instead, these faults appear as phase-to-phase faults on the delta side of the transformer. Fast acting trip circuitry in the controller and/or gate drivers must then shut down the IGBTs in a timely. The third vertical line represents a locked rotor or bound shaft condition. Over-Current (Electrical Overload): In different operating conditions, electrical devices will sometimes start to draw more current than their overall capacity. Do not open a radiator or heat exchanger pressure cap while the engine is running. The motor can not run at absence of phase. A fault is a general term that describes any sort of malfunction Miswiring. Typically an induction motor will run by a voltage of 230 Volt or 460 Volt, 3 phase 60 Hz in USA and be controlled by a control voltage of 115 Volt AC or 24 Volt DC. After the heater elements cool, reset the starter to resume oper-ation. I know that stepper motors can preform better with higher input voltages so that they can change their currents faster. This overloading of the pumps can be caused by various reasons as discussed below. Two logic inputs. Because of a motor's characteristics, many common overcurrent devices actually offer limited or no protection. the motor has carbs on it and is a 6 cylinder. TROUBLESHOOTING (SERIAL INTERFACE SPINDLE) B–62755EN/01 392 Item Cause of trouble Check procedure Remedy 1 Defective fan motor of motor Check if fan motor is rotating. Check for and correct: † Excessive motor load. P2118 Toyota Description The Electronic Throttle Control System (ETCS) has a dedicated power supply circuit. VFD overvoltage fault, operating normally. The load is the reason for the application. Read expert vehicle reviews and award-winning feature content at Car and Driver. Check motor and pump alignment. This causes the generator’s voltage and frequency to drop as well, until the rpm recovers. Soft starts reduce the start up transient, but, not the shutdown transient. Because the motor is drawing more current, it heats up. If yes, check these things: Turn only the main breaker on for the machine look at LED displays on drives. Motor bearing failure — Motor bearing failure is the #1 cause of motor failures and can be caused by lubrication problems, contamination, bearing current, shaft misalignment or side loading Single-phase motor winding failure — One phase is open in the motor circuit, which can be caused by a blown fuse, open contactor, open motor lead or bad. Low line voltage. motor can damage the motor, the Mamba Monster X, and your batteries. Understanding the basics of an overcurrent condition and the purpose for overcurrent protection will establish the foundation for our discussion. Two identical applications had undergone unscheduled outages in the previous 12 months. This condition would result in a motor drawing locked rotor current during start-up. Electric motors in your A/C can run for a long time, but if a motor runs for too long, the insulation around the wires can deteriorate and cause an electrical short. bearings quality,focous on zero-2 motor assembly, 2 check no load amp. Instantaneous power failure of 15ms or longer. Standard PTC heaters are not suitable for soldering. 4) Motor speed 965rpm. An overcurrent can be caused by overloading the circuit or by a short circuit, a ground fault, or an arc fault. But a VFD’s output uses dc pulses to induce motor motion, and those pulses can cause interference with electrical signals through the motor and the motor cables—damaging components and degrading overall machine performance. This causes problems like harmonics, voltage imbalances, current imbalances, etc. Damage may be serious unless the overcurrent protection device opens in time to prevent damage. The feeder conductors to the fire pump are 1 AWG copper with THWN insulation in 1. 1 lack of maintenance. CoolAutomation is the industry leader in Internet of Climate (IoC) technologies. Historically, the causes of motor failure can be attributed to: Overloads 30% Contaminants 19% Single-phasing 14% Bearing failure 13% Old age 10% Rotor failure 5% Miscellaneous 9% 100% From the above data, it can be seen that 44% of motor failure problems are related to HEAT. Texas Instruments (TI) Motor drivers support forum is an extensive online knowledge base where millions of technical questions and solutions are available 24/7. 6kV motor was running with only 7 percent overcurrent, but an 8 percent overvoltage. Clogged filter. 13 common causes of motor failure and what to look for and how to improve asset uptime from Fluke. The DRV8825 is rated for 45V motor input. The cycling thermostat is supposed to turn on and off the heat to maintain the proper temperature. Over-currents are due to a short circuit. A mild overload was identified by examining the stator current of this motor. Overcurrent protection immediately trips the main circuit breaker and cuts the power. Is it the Drive/Amplifier? Power the drive back up, if the #8 stays on, the problem is within the drive and it will need to be repaired. a conveyor, causing the motor to work harder and draw more current. The motor cable screen must be terminated to the drive heat sink or mounting plate and to the motor frame. we did change 1)armature firing card. Overcurrent is generally smaller than short circuit current and within 6 times of the rated current. Other causes include issues with the supply, operation environment or lack of maintenance. Voltage at the drive output compared to voltage at the motor peckerhead is within 1% between all three phases of the drive that faults most often. The higher current flow causes more heat to develop inside the motor. The over-current relays are connected to the system, normally by means of CT's, for small power motors direct to supply line. We can help you clear your errors as quickly as possible, and we can let you know if they require additional support or a factory repair. Motor contactor CES, overload relays and accessories. abnormal conditions. No matter which type of overload is used it must be a Class 10 overload or capable of providing Class 10 protection. Check the following: - Motor power (P0307) must correspond to inverter power (r0206). Overcurrent Protection Basics. Plugged it back in after cleaning it, the thing started heating up like a stove top and you could smell it cooking. We need to setting the value of overload relay properly depend on our application and motor full load ampere. Fault 29 - Analog In Loss - An analog input is configured to fault on signal loss. If the capacitor has failed the symptom is that the motor won't start. SOF and tnF faults can also be cleared remotely by means of a logic input (parameter Detected fault reset assignment rSF page 91 in COnF/FULL/FLt-menu). valve Defect of compressor Malfunction of outdoor unit fan motor Faulty contact of fan motor connector Defect of fan motor Defect of fan motor driver Overcurrent of inverter compressor Defect of compressor Defect of. Incorrect winding data that increases the magnetic flux levels as compared with design levels will result in increased no-load current. IoC is a universal concept that enables HVAC systems to be controlled, serviced, optimized, and managed remotely. “Dead spot” is a common term for a certain orientation of the rotor at which the motor (PSC or split phase) will not start. For example, the electric motor incorporated in an air conditioner compressor may overheat due to internal wear and may pull too many amps. Besides that, a drive may also experience overcurrent trips or possibly a motor-related fault such as an overload. A motor connected to a run and start capacitor may still attempt to start if one or both of the capacitors has failed, and this will result in a motor that hums and will not remain running for long. Because of a motor's characteristics, many common overcurrent devices actually offer limited or no protection. By its very nature, the D. According to NEC article 430-32, continuous duty motors of more than one horsepower have the option for overload protection if they are larger than 1500 horsepower of using. Visually inspect the related wiring harness and connectors. 1): • Mechanical damage • Excessive moisture • High dielectric stress. The negative sequence relay protects the generator and motor from the unbalanced load which mainly occurs because of the phase-to-phase faults. Prior to beginning an analysis of a specific electrical item, it is assumed that the person responsible for determining the cause of the fire will have already defined the area or point of origin. causes and effects of over voltages in power system Over voltages are caused on power systems due to external and internal influencing factors. The repair technicians at TigerTek have seen it all when it comes to broken servo motors, but some issues are more common than others. Welcome back! If you missed part 1 of this series, I discussed the necessity of cycle-by-cycle over current protection in BLDC motor drives and how to sense the motor winding current. The most common forms of noise is probably RF waves and electromagnetic energy. Short on power supply causing voltage dip. The cause of the detected fault must be removed before clearing by turning off and then on. 4) Motor speed 965rpm. Torque in DC Motor depends upon the constructional as well as operational parameters. Brushes displacement from geometric neutral axis causes ring fire in DC locomotive traction motor. To get the codes, cycle the ignition key On - Off - On - Off – On within 5 seconds. Cummins heavy-duty engine - Rugged 4-cycle industrial diesel delivers reliable power, low emissions and fast response to load changes. We provided Core Balance CT (CBCT) with ELR for motor rated above 5. Possible causes for overcurrent include short circuits, excessive load, and incorrect design. Eventually all that dust ends up in the blower motor, which can then overheat, causing the fuse to burn out and possibly even catch on fire. The motor is not wired correctly. Therefore the motor is receiving this current as well. Defective drive motor. Techniline - diagnostyka i naprawa falowników i serwonapędów. In the case of an over-current situation, the thermistor body temperature rises and quickly reaches the transition temperature. 41-101U Type CO Overcurrent Relay 4 2. This article presents a basic explanation of electric motor construction and operation along with twelve problems that can be encountered with their use. Typically, a line filter to the drive input is unnecessary, except in certain cases, such as to meet CE compliance or when noise from the drive reflects back onto the input power and causes interference. August 6, c. 1 ELECTROMAGNET. I experienced similar problem of my MH55 Ingersoll Rand Compressor tripping off on MTR Overld. Another possibility is that the driven load is jammed, binding or mismatched. Storm damage to power conductors is a primary source of single-phase conditions. About 99% of these are relays. In addition to providing overcurrent protection, a circuit breaker provides a manual means of energizing and de-energizing a circuit. Both internal and external motor overload protection work the same way. this alarm comes up because of a bad power supply. Circulating currents are a problem in large AC and DC motors of over 100 hp. YORK AC Indoor Unit Display. Motor protection depending on size and voltage level (on photo 3-phase asynchronous motor LeroySomer P280 S-8, 55 kW) Instantaneous. Over current (Excessive load over a period of time) Over voltage (Overhauling type of load) Over Heat (High ambient temperatures-Overloading) Are the thermostats in the motor tripped (N/C contacts)? Attempt a reset. the drive can cause a number of failures. If tripped determine cause and correct problem. Known causes of dynamic park brake lock-up on the RXV. The primary overcurrent protective device(s) shall be selected or set to carry indefinitely the sum of the locked-rotor current of the fire pump motor(s) and the pressure maintenance pump motor(s) and the full-load current of the associated fire pump accessory equipment when. Poor soldering is a common cause of in-flight failure! Ensure connectors are. 4 Motor Control menu. Motor overcurrents can produce excessive heat that may damage the winding insulation and for small motors may even cause a failure of the very small diameter wire windings. IoC is a universal concept that enables HVAC systems to be controlled, serviced, optimized, and managed remotely. Possible causes for overcurrent include short circuits, excessive load, incorrect design, or a ground fault. Overload protection is a protection against a running overcurrent that would cause overheating of the protected equipment. A surge in current would cause an over voltage. Visually inspect the related wiring harness and connectors. In order to protect against thermal overstress a PTC thermistor is used. If you wish to change the gearing, motor, or battery, you must check your motor temperature frequently on the first run. By reversing the power supply to the motor, the current in the rotor coils, and therefore the north and south poles, is reversed. ・Estimates the inertia moment value applied to the motor shaft from the load, and automatically controls the ASR system constant. Several types of motor failure can cause the motor to draw excessive current and trip the overload breaker. The AC supply voltage may be missing or no longer in sync. The characteristic curves of the lower specific speed pumps indicate that such pumps have overloading features. An OCPD protects against excess heat generated by overcurrent from such causes as overload, short circuit, or ground fault. The designer calculates the power rating of the resistor to stay under the temperature limits during braking. Depending on the control characteristics (gate resistors, capacitors, command voltages, etc. it dsplays the latest fault Cause and the fault Current or fault phase. Overcurrent alarm (HCL). 3 Dirty motor. Fire pump overcurrent. You can search motor drivers IC content or ask technical support questions on everything from brushless DC (BLDC) and brushed DC (BDC. For example anything that involves a power supply, transformer, heating element. abnormal conditions. These inrush currents typically last only a fraction of a second, and seldom cause a problem. Possible Causes and Solutions. Negative Sequence Relay Definition: A relay which protects the electrical system from negative sequence component is called a negative sequence relay or unbalance phase relay. A fault is a general term that describes any sort of malfunction Miswiring. With drives and motors, there are a few common problems that application engineers tend to see the most. Protection and Control. M aintenance experts agree that excessive heat causes rapid deterioration of motor winding insulation. settings of overcurrent protective devices Motor The Time-Current Curves for motors are also What would cause a. By its very nature, the D. Answer / varun tripathi. engine codes. One blower functions to cool the motor during its operation and is usually made from plastic and is visible when you open the furnace door. Common Issues & Causes in Servo Motor Systems. Common Causes of Electric Motor Failures. As an example, if voltage unbalance is 1%, then current unbalance could be anywhere from 6% to 10%. The cause of this malfunction has to be established quickly and a suitable remedy found. Bearing Failure 12% 5. 12 Calculation of phase fault overcurrent relay settings 9. The suite of overcurrent elements (51, Section 8) is generally considered backup transformer protection, or for protection of the bus and backup protection for the feeder relays. Moisture in the motor conduit box. running, or shortly after the motor stops. Check for bent crankshaft. Job after a few hours of intense vibration fault repair Fault phenomenon: a used CNC FANUC 0T CNC lathe, normal boot-up of all action, high-speed servo-feed system sports a smooth, low-speed non-crawling, processing of all parts meet the required accuracy. † Use the Fault listing table below to find and address the root cause of the problem. Fuses, circuit breakers, and current limiters are commonly used overcurrent protection (OCP) mechanisms to control the risks. Motor protection relays protect against damage and downtime caused by problems such as overcurrent, phase loss, voltage unbalance and more. The most common cause of motor failure, and arguably the most difficult to overcome, is low resistance. Consequently, a defect can induce high losses in terms of cost and can be dangerous in terms of security and safety. This may cause damage to. The repair technicians at TigerTek have seen it all when it comes to broken servo motors, but some issues are more common than others. cause of the high efficiency (as great as 95%) and small size for a given delivered power. The Be124 generator controller alarm monitoring system opens the Generator Circuit Breaker (GCB) in a way to protect the generator itself. As an example, if voltage unbalance is 1%, then current unbalance could be anywhere from 6% to 10%. The feeder conductors to the fire pump are 1 AWG copper with THWN insulation in 1. Industrial motor drive design. Storm damage to power conductors is a primary source of single-phase conditions. Defective start relay. Allowing a motor to reach and operate at a temperature 10°C. For dsPIC DSC’s for PMSM Motor Control Start with the: 70MIPS dsPIC33EP64MC206; Microchip offers both MIPS and ARM Cortex MCU's for high performance, 32-bit motor control. But this fault resolve after chaning the Servo motor. Standard Motor Protection and Control Features. P2118 Toyota Description The Electronic Throttle Control System (ETCS) has a dedicated power supply circuit. The fuse is a reliable overcurrent protective device, primarily used as a circuit protection device for overcurrents, overloads and short-circuits. If there is a sudden drop in load, the motor speed may increase quickly, causing a regenerative load. Causes and Effects of Transient Voltages file:///C|/Users/Shannon/Documents/Causes%20and%20Effects%20of%20Transient%20Voltages. If either current or voltage increases to a level that the inverter is not rated for, it can cause damage to components in the device, most frequently the inverter bridge. As the separately installed belt or shaft driven compressor builds up back pressure, the motor current increases due to the increased motor load applied. In order to protect against thermal overstress a PTC thermistor is used. bearings quality,focous on zero-2 motor assembly, 2 check no load amp. Size OCPDs to keep conductors from exceeding their ampacities. MPCBs are UL 489 Listed as circuit breakers and verified as motor overload relays. These devices feature high performance peripherals tailored for high speed, closed loop motor control. Issue: Axis or System runs uncontrollably The velocity feedback, position feedback device or velocity command signal wiring is incorrect or open. Overcurrent fault. Over-Current And Overload Situations As the load on an electric motor increases, the spinning rotor starts to slip more and slow down. The read resolver position is then taken as the offset between the motor and the resolver. motor can damage the motor, the Mamba Monster X, and your batteries. Single Phasing 15% 4. This will result in an overcurrent through the motor winding. Loose power connections cause overvoltage and overcurrent conditions, blown fuses, and frequency converter damage. 1 ‘51’ overcurrent protection 43 9. If the output load has a clutch, that may cause a VFD overvoltage fault. Shorts in the armature windings can draw excessive current. Overcurrent faults are the most common faults that will shut down a drive. Features RXIIK 4 relay − Negative sequence overcurrent relays are used to detect unbalanced load on a generator which may cause exces- sive rotor heating. why causes the burnt of AC Electrical Motor ?. Most of motor winding failure occurs due to overload. Rather, a device with an interruption rating of 10,000 amps is certified to be able to stop a fault current of that magnitude once having opened. “Overloads” are currents that can damage a circuit if allowed to continue for a sufficient time, whereas “short circuits” and “ground faults” are high currents that can cause immediate damage. LOAD TA CHOMETER. In this article, we will cover types of overcurrent, what overcurrent protection devices are, and their place in an electrical circuit. The better choice would be to use activation time characteristics, or the so-called inverse time-delay characteristics, selected to operate the Motor Protective. The next two issues that can cause inverter failure are over-current and over-voltage. After the heater elements cool, reset the starter to resume oper-ation. 15 Earth fault protection 9. This can cause a drop in pump efficiency and an increase in power consumption by pumps, which may cause the motor to trip. Buck-boost transformers have dual-voltage primaries and secondaries. Covering ratings of 0. Possible causes for overcurrent include short circuits, excessive load, and incorrect design. A study commissioned by the Electrical Research Associates (ERA) of the United Kingdom in 1986 indicated the most common causes of motor failure are: 1. I just wanted to make sure what I was reading was not erroneous. If this is the case, a dynamic brake might help absorb the energy. Thermal stress can potentially cause the failure of all the major motor parts: Stator, Rotor, Bearings, Shaft and Frame. most common causes of servo motor failure Keeping your servo motor maintained and running in prime condition is vital to any industrial business, robotics enterprise, or CNC machine. An OCPD protects against excess heat generated by overcurrent from such causes as overload, short circuit, or ground fault. All faults on a feeder should open the feeder overcurrent protection rather than the service overcurrent protection. A good example of overload overcurrent is the overcurrent that is experienced when a motor is mechanically overloaded by excess heat, excess friction or mechanical faults. The compressor can only be put on again after the air in the storage has been used up. However, these traditional methods do not always meet the design criteria;. Overload protection that open circuit when there is a danger of the motor overheating. (b) Electric power and lighting circuits. Historically, the causes of motor failure can be attributed to: Overloads 30% Contaminants 19% Single-phasing 14% Bearing failure 13% Old age 10% Rotor failure 5% Miscellaneous 9% 100% From the above data, it can be seen that 44% of motor failure problems are related to HEAT. Unlike old-fashioned overload relays, modern relays are smart electronic devices that can tell the operator which condition triggered a shutdown. Buck-boost transformers have dual-voltage primaries and secondaries. Why these codes? Well, these are the most common codes. Rather, a device with an interruption rating of 10,000 amps is certified to be able to stop a fault current of that magnitude once having opened. Two logic inputs. They each have an ABB ACH550-UH 10 hp drive. Button SETO SET Fault histoty check : Pressing the ESC button than 5SeC. There is only one current operated element in the relay, no voltage coil etc. Several types of motor failure can cause the motor to draw excessive current and trip the overload breaker. If using a circuit breaker, select a breaker with a time delay, again the same type you would use with a motor. The short is causing too much current to flow through the power module inside the amplifier and will eventually cause it to break. Note: Some circuits are just demonstration circuits and need "damper diodes" (protection diodes) to reduce spikes. LOAD TA CHOMETER. Voltage at the drive output compared to voltage at the motor peckerhead is within 1% between all three phases of the drive that faults most often. If the VFD has “faulted”, proceed to determine the cause and correct the problem. The lower the ohmic value of a resistor, the faster it can stop the motor and the more heat it generates. Check for damaged components and look for broken, bent, pushed out, or corroded terminals. An overcurrent fault could be the result of overtemperature. This in turn will result in damage to the winding insulation. For instance if it says the trip was DRIVE Over Current vs MOTOR over current, but the 250A was the MOTOR current at that instant, then that points to a failed IGBT, where it is likely shorting through the case to ground, or multiple IGBT failures where they are firing at the wrong times. You sure the VFD is sized correctly? Did you put in the Motor NP information correctly? F013 Ground Fault 1(3). Why these codes? Well, these are the most common codes. It does not happen always but very often and on both machines. Over current (Excessive load over a period of time) Over voltage (Overhauling type of load) Over Heat (High ambient temperatures-Overloading) Are the thermostats in the motor tripped (N/C contacts)? Attempt a reset. motor, about 6 to 8 times normal running current. If this occurs the motor is described as being “burned out” and must be rewound or replaced. Compressor Overcurrent Protection. Introduction Recent claims by fuse manufacturers regarding the arc-flash and simplified-coordination benefits of fuses do not tell the entire story regarding which. Clogged filter. Overcurrent is generally smaller than short circuit current and within 6 times of the rated current. IGBT Overcurrent and Short-Circuit Protection in Industrial Motor Drives. , could be that the motor is not delivering torque sufficient to accelerate the connected load to speed. If this occurs the motor is described as being “burned out” and must be rewound or replaced. Most HVAC technicians know HVAC compressors pull a lot of amps on startup. Historically, the causes of motor failure can be attributed to: Overloads 30% Contaminants 19% Single-phasing 14% Bearing failure 13% Old age 10% Rotor failure 5% Miscellaneous 9% 100% From the above data, it can be seen that 44% of motor failure problems are related to HEAT. The MIG II provides time overcurrent protection that can be set from 0. Risk of burn due to high 'temperature at the motor surface. If the VFD has "faulted", proceed to determine the cause and correct the problem. If it is an average DC motor with commutator etc, there is back EMF caused by the motor acting as a generator. The manual says to look for overcurrent cause and - Answered by a verified Pool and Spa Expert We use cookies to give you the best possible experience on our website. This condition causes the normal line amperage to increase to 230% of normal in one phase and 115% of normal in two phases. The vast majority of bearing failures in electric motors and electric motor-driven equipment are due to mechanical and thermal causes. A fault is a general term that describes any sort of malfunction Miswiring. So to protect the stator against over heating, embed resistance temperature detector or thermocouples are used in the slots below the stator coils. HECOAllSystemGo 17,239 views. CoolAutomation is the industry leader in Internet of Climate (IoC) technologies. Check programming. If someone is not comfortable working with electricity, an electrician can be called in to determine the cause of the short and repair it. But this fault resolve after chaning the Servo motor. Both overload and short circuit can cause excessive current flow. i found the current values exceed far beyond normal working and this no doubt is the initial cause of the motors failing. We’re here to help! The list below features some of the most common reasons why Allen-Bradley PowerFlex drives can fault and how to solve those issues. August 6, c. Power supply is low. Possible Causes and Solutions. The suite of overcurrent elements (51, Section 8) is generally considered backup transformer protection, or for protection of the bus and backup protection for the feeder relays. If an overload occurs, the compressor motor will not restart, even when the tank pressure drops. Possible causes for overcurrent include short circuits, excessive load, and incorrect design. Most of the electric motor failures occur at start up due factors such as low insulation resistance, over-current or mechanical failures. Reasons for Overload Protection. This causes more resistance against the motor's ability to turn freely. Phase-to-Phase Insulation. Over current (excessive load over a period of time) Over voltage (overhauling type of load) Over Heat (high ambient temperatures - overloading) Are the thermostats in the motor is tripped (N/C contacts)? No tach signal Attempt a reset Make sure the controller is getting a start signal (N/O contacts). only designed to protect the motor from overload or failure to start overcurrent. 2 About controller Here are some troubles, possible causes and solutions, described as follows. Fault listing Fault Code Fault Name In Panel Description and Recommended Corrective Action 1 OVERCURRENT Output current is excessive. As stated earlier, excess current flowing through a motor winding will cause overheating. Check the "Possible Causes" listed above. If the motor gets too hot, reduce the pinion size, increase the spur size, or reduce the pack voltage.