3 phase system short circuit protection.

Hello everybody .

After working on single phase power converters and inverters , am currently working on a trade/repair company , mainly 3 phase motor drives , servos , and other industrial material .

Back in the days i was using the famous light bulb trick on single phase systems for short circuit protection .

Is there a way to use the light bulb trick or other method as a protection from 3 phase systems shorts on the SWITCHING SIDE .

You can think of putting a small protection relay that can serve for short circuit, over load, phase unbalance etc. Based on the model you select you can have flexibility of changing the set values. Try a google search for the relays with the motor rating you need to run.

Why not just stack some lamps in series until you are above your working voltage?

Not sure exactly what you are asking but the below is what I have used as a 3 Phase Ground Fault detector circuit for 480 Volt 3 Phase Delta power.



During normal operation all of the bulbs will glow dimly. If any phase shorts to ground the shorted phase bulbs will extinguish and the remaining bulbs will increase in intensity. Pretty straight forward.

Ron

Reloadron said:

Not sure exactly what you are asking but the below is what I have used as a 3 Phase Ground Fault detector circuit for 480 Volt 3 Phase Delta power.

View attachment 90739

During normal operation all of the bulbs will glow dimly. If any phase shorts to ground the shorted phase bulbs will extinguish and the remaining bulbs will increase in intensity. Pretty straight forward.

Ron

Click to expand...

Nice but actually am trying to avoid shorts between phases , i think as mbarazeen said , i just use a differencial circuit breaker with fast tripping .