Differential Relay Tripping

Looks like the transformer could be alright while the HT motor isnt, but then the information is so scarce I would call this a wild guess!

"...seems to be okay...", if it were the differential wouldn't be tripping. Your job is to change "seems" to "is verified", until then no one can help you.

What tests have been run on the CT and the Motor??

You seem to want to know the problem without troubleshooting the equipment...this is not possible...

Since we don't have a circuit diagram, it's impossible to give a good answer.

A differential relay trips (is energized) when two currents are not equal. It is commonly used in Ground Fault Interrupter (GFI) circuits.

Are we talking about a GFI circuit? If so, it indicates that there is a ground return path in the HT motor where current is returning to the supply through the ground and not through the neutral.

This is just a shot in the dark, but someone left the discomboobulator engaged. That fed back to the HT CT dorkifier, resulting in crankulator lifting. The resulting steam issuance, fogged the glass over the tripulator, resulting in breakage of the optical path, so that the tripulator is donkified.

Replace the opernator with someone who knows how to properly diagnose the circuit.

Just get rid of that pesky differential relay.

Are those UL rated?

Rating? Rating! We don't need no stinking UL rating.

We are LynDoor™Industries.

We only make the best. The very best. You will never find a better .............whatever.

Those other stupid rating services are bad, really bad. None worse anywhere. People are saying that the others are crap and LynDoor™Industries is the best! The very best in the entire, whole, complete, only solar system.

I saw thousands of people dancing in the streets, with my own eyes, on TV and they are chanting LynDoor...........LynDoor..............LynDoor..............LynDoor.......LynDoor

Somebody needs to hide the Trump Kool-Aid from this guy!

Next thing you will be saying Lyn-Dor Industries Mission Statement is "Make America Great Again".

I just want one that says "America First and Forever".

Since you mentioned it, Herr Drumpf's motto is really "Make America Hate Again".

I am sorry you feel that way. I really do not think it will be that way. I expect people can find common ground across the board, work together, and continue to improve this country. It stops when groups stop repeating patterns that leaves them out of the dialogue, interferes with their productivity and prosperity, or that results in illegal activities that get them into problems.

Law is intended to be the final authority in this country. Since when are some people exempt from obeying the law, or from the consequences of breaking the law? There are supposed to be NO class distinctions here in this country, and if there are, they need to be uprooted.

I refuse to discuss this any further.

I should have thought of that myself. Here at insubordinate power and light, we use small jumpers on many things just to keep it all running - NO MATTER WHAT.

If you believe that, I can broker a deal on Lyn's dream home in Az.

Nah, he has the reverse end of the discombobulator connected directly to the boiler fire eye, instead of the cat's head.

You have not made it clear if the CTs (of one phase) connected to the differential relay have only the transformer between them or both the transformer AND the motor.

Nor have you told us the relay type, transfo ratio, CT ratios etc.

To avoid false tripping, Differential relays have to cope with the problem that at high overcurrents, one of the two CTs with equal primary currents may saturate before the other - giving unequal secondary currents exceeding the "differential" causing a false trip.

When a transfo is protected, the CT ratios may not perfectly match the protected transfo ratio. There is the additional problem that the primary inrush current of the transfo only goes through the primary CT but not the secondary CT, always giving a differential current. There are similarities between the inrush current of a transfo and that of a motor but it does not follow that the differential relay tolerates both without a false trip.

The simplest reason for the tripping, if this is a new installation, is that the relay/CT system is wrongly connected, was wrongly designed or you have not used the designed relay settings.

If it is a proven installation, it may be a motor fault.

If you have taken a risk and bypassed the relay (during starting) to prove that the motor runs OK with relay active once it has started, it would have helped if you told us that.