The breakage of the squirrel-cage rotor rods is an insidious malfunction: the engine runs, but with jerking, overheating and loss of torque. Let's look at diagnosis of broken rotor rods.
What happens
The “squirrel cage” rotor consists of rods closed by rings. When one or more rods break, the symmetry of the currents is broken, the motor loses torque and operates with pulsation.
Symptoms
- Jerky operation, torque pulsation.
- Loss of power under load.
- Increased slip (strong drop in speed).
- Overheating of the rotor.
- Current ripple stator.
Diagnostic methods
| Method | What it shows |
|---|---|
| Analysis of the stator current (pulsation) | Indirect sign of a break |
| Measurement of no-load current | Ripple when breakage |
| Special analysis of the current spectrum | Precise detection |
| Inspection of the rotor during disassembly | Direct detection |
What to do
Breakage of rods is eliminated by repairing or replacing the rotor. Sometimes soldering or welding of the rods is possible, but more often rotor repair is required. The exact cause of the jerking is determined by diagnostics.
Does the engine run jerkily and lose torque in Tashkent? Elektromotors engineers will identify broken rotor rods - contact us.