Hot stall time vs Cold stall time [motor]

[fiadr]

Whats allowable stall time? why there is a hot stall time & cold stall time for motors?

 

[dick_freebird]

Electric motor worst case current is locked-rotor (stall).
But the failure mode is overtemperature in the insulation,
most commonly. You get to temperature by time and
power (I^2*R), and starting from hot you have less
margin to the critical temperature so less time allowed
at the problem-making condition.

 

[chuckey]

Also the resistance of copper winding are lower when they are hot so more current!.
Frank

 

[fiadr]

Electric motor worst case current is locked-rotor (stall).
But the failure mode is overtemperature in the insulation,
most commonly. You get to temperature by time and
power (I^2*R), and starting from hot you have less
margin to the critical temperature so less time allowed
at the problem-making condition.

How will you know when the motor is starting as hot or starting as cold??

 

[dick_freebird]

Those two cases are provided for you by the manufacturer,
for you to work from. Cooling and care, is on you.