Strostkovy...... BS is to be squashed.... We do not DO BS here.
................
The physics haven't changed.
Correct...... Clamp on measures the field resulting from the current. If it does so accurately, then that current IS FLOWING.
You don't agree? Argue with the physicists, not with me. You and Rozen are off base.
The breaker is going to respond to the current, whether that current is in-phase, or out of phase with the voltage. It cannot help doing so... that is what it does.
Ok, back out of la-la-bullcrap land.
What you CAN do about excess current in the breaker, which you may already have done, is to install power factor correction capacitors (PFC capacitors).
If you did that, then the out-of phase current is nearly all gone, the "PFC" capacitors cancel it. That is a valuable technique for getting an RPC to operate on a limited breaker, so long as the breaker is not popping from the capacitor surge at turn-on. It takes the idler motor magnetizing current out of the picture as far as the breaker is concerned.
The "idle" current in a motor that is running with no load, is mostly "magnetizing current" that is out of phase with voltage. it can be 30 to 50 percent of full load amps. Power factor may be as low as 0.1, so it represents very little actual power.
A 30 HP motor running no load might draw as much as 25 to 30A, possibly more, depending. If your idler is drawing 8, you likely have the power factor corrected up considerably, per the Fitch Williams design. A W.A.G. would put the PF around 0.6 or 0.7 looking from the breaker. Not bad. You do NOT want to go over 0.9.
Incidentally, if you have a motor controller on that motor, the PFC capacitors have to go before it, because the overload is figured for the bare motor current, not the PFC-corrected current.
How about your capacitor blowing issue? Any movement there?
Another thought came to me, late, but relevant.
That voltage issue...... it may be a symptom, if true, of a problem.
The way the "balance" capacitors work is to cancel the inductance of the idler motor. But, the criterion for cancellation is that BOTH the inductance and the capacitance "disappear" when the cancellation is exact. That condition is also known as "resonance", in this case a series resonance.
You DO NOT WANT that, because it causes a near short across the line, with high line-to-line voltages on the capacitor, and heavy current flow. Just what you do not want. It can cause the exact problem you see.
Is that what you have (or had)? We don't know, but it sounds possible. Only you can know for sure.
If you have that condition, it means you have over-corrected, with too much capacitance, and have gotten too close to "resonance" in the unloaded condition. That can happen if trying to correct too far in the LOADED condition, with the load motor running.
The load motor "damps" the resonance, so you will NOT have any idea what the unloaded condition will be. It is easy to become surprised by the high voltages, and blow parts.
The usual system, and I think the Fitch Williams plan says this, is to correct UNLOADED, to no more than 10% over the incoming voltage, and accept whatever drop occurs under load. A better number is 8% over.
if you try to correct too perfectly in the loaded condition, you may have radically high voltages unloaded, and very heavy currents. Always do your correction UNloaded.
If you feel you MUST correct more, then really, you probably actually need a larger idler. But you CAN do one thing...... you can connect the added capacitors, the ones in addition to what does 10% high unloaded, AFTER the start contactor of the LOAD motor. Not after the overcurrent sensor, but after the start contactor.
In that way, you only have them connected when the load motor is on, and there is probably no issue with the no-load voltages of the idler, because when the load motor is disconnected, so is the added capacitance.
(the contactor does need to be able to handle the inrush to them)