The 7 most common breakdown causes
- A flat or faulty battery. Battery trouble is often the main cause of breakdown issues.
- Alternator trouble. Without an alternator, the battery can't be charged up by the engine.
- Damaged tyres or wheel.
- Electrical problem.
- Keys and alarms.
- Misfuelling.
- Clutch cables on manual vehicles.
Some motors burn out after years of overuse, especially if they operate at too high a voltage. The excess flow during winding causes them to break down. Here are some of the most common reasons why your motor stopped working: A short circuit can occur in the winding.
Check for shorts between the power wiring and ground. Select ohms resistance on the multi-meter and set for the 30,000-ohm range. Touch one lead to each motor power lead and the other to the metal motor casing. Any value less than about 0.2 mega ohms is a reason to discard the motor.
Overload Protection Test:
- Measure the normal motor running current (i motor).
- Turn off the motor and let it cool for about 10 minutes.
- Calculate the following ratio: i (motor) / i (overload min FLA).
- Set the overload to its minimum FLA and turn on the motor.
- Wait for the overload to trip.
If an electric motor operates at too high a voltage, excess current flowing through the windings can cause them to become hot and burn out. While it is normally not practical to repair small, direct current (DC) motors that have burned out, other motors can be repaired by rewinding.
Overheating in an electric motor can happen for a variety of reasons. The most common causes of overheating include: A motor that's too large can waste expensive energy, and a motor that's too small will be unable to handle an excessive workload — leading to greater stress and heat.
Blown FuseOne of the most common problems that prevent electric motors from turning on or operating at all are blown fuses. If a fuse blows it will need to be replaced with a fuse of the same amperage and the breaker will need to be reset.
Heat is the number 1 cause of Brushless motor failure. You want to keep your motor temps around 150/160F. Around 175F the magnets start to demagnetize and you start losing power. The only other enemy of a brushless motor is dirt in the bearings.
The Most Common Electric Motor Breakdowns
- Bad Insulation Resistance. This is one of the most common breakdowns and, sadly, one of the most difficult to deal with.
- Electrical Overload. Essentially, this means that an excess of electrical current flows through motor windings.
- Vibration Problems.
- Overheating.
Whether the blades aren't spinning or the fan is making tons of noise, most issues with an electric fan are caused by poor lubrication or blockages in the vents. To solve most problems with an electric fan, disassemble the fan, lubricate the central pin and bearings, and clean out the vent and motor case.
If it starts to run, stops by itself, and then will start again after a while: it is pretty likely to shutting down due to internal overload protection. Check to see if the motor spins freely; perhaps the bearings are worn.
With a multimeter set to low ohms (usually 200), test between each winding terminal and the metal casing of the motor. If there is any reading on any of these then the motor is bad, do not use it. You may find that when it runs ungrounded that the casing becomes live at up to supply voltage.
Yes, electric motors can get weaker over time. Bearings wear out and electric insulation breaks down and can start developing shorts in the winding's.
Motors can get "weak" with age, yes. What happens is that the winding insulation starts to leak to the frame, so not all of the power going to the motor is performing useful work.
The motor is to be earthed properly. Once protective relays are connected in the system the system get tripped when the live terminal of any phase get earthed. Once tripping happens proper Megger check to be carried out for cable and Motor, to find the cause of tripping. The tripping can be due to Earth fault.
A ground fault (earth fault) is any failure that allows unintended connection of power circuit conductors with the earth. Such faults can cause objectionable circulating currents, or may energize the housings of equipment at a dangerous voltage.
How to Troubleshoot a 3-Phase Electric Motor
- Take input voltage to the motor using the volt ohmmeter. The motor-specified voltage must be present on all three phases.
- Examine the motor's electrical connections and terminals.
- Remove motor voltage and disengage the motor from the machine that it is running.
- Check the motor for heat or burnt smell.
This is called phase failure or single phasing. If a three-phase motor is operating and loses one of the phases, the motor will continue to operate at a reduced speed and experience vibrations. The current will also increase considerably in the remaining phases, causing an internal heating of the motor components.
