What can burn out a 3 phase motor ? Can turning it on and off be effective?

Thread Starter

dashhossein

Joined Jul 30, 2020
47
Hello everyone ...
For a project, I want to make an escalator smart with a number of PIR sensors
So that the escalator turns off after one minute of not using it
And for example, turn on 20 seconds later
If this cycle continues, can it damage the engine?
The specifications of this motor are 9 kW and 20 amps
The starting current is 22 amps and after stabilization is 8 amps.
In general, what can cause damage to the engine?
 

MaxHeadRoom

Joined Jul 18, 2013
23,150
Continuous stop starting of a 3ph motor can cause (over)heating especially with a permanent load.
You would need to monitor this closely.
A clutch system may be one answer?
Max.
 

andrewmm

Joined Feb 25, 2011
1,496
Many escalators and moving walkways I see at airports have a similar system, when I come back late at night everything is off till you approach,

So yes it can be done,

I'd suggest a bit of circuit monitoring is need,

Question is , if were worried about heat, does the motor cool down when its on ?
I assume it must do, otherwise you have a motor that can only run for a limited time anyway.

If so , then don't stop the motor if its to hot,
 

Thread Starter

dashhossein

Joined Jul 30, 2020
47
Many escalators and moving walkways I see at airports have a similar system, when I come back late at night everything is off till you approach,

So yes it can be done,

I'd suggest a bit of circuit monitoring is need,

Question is , if were worried about heat, does the motor cool down when its on ?
I assume it must do, otherwise you have a motor that can only run for a limited time anyway.

If so , then don't stop the motor if its to hot,
the motor are always on
yes i need a real monitor for that
 

EMorton

Joined Aug 24, 2020
1
VFD is great step forward but not all motors are designed to work with higher switching frequencies. Old squirrel cage motor may not shed enough heat.
 

shortbus

Joined Sep 30, 2009
8,594
Would doing this even save any energy? Do to the higher start current over the running current? If the escalator was originally engineered correctly when there is no people load on it, it isn't even using much energy. Then wouldn't there be human anger when they have to wait for the escalator to start when they come up to it?
 
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