PHOTOS of my 17.5 HP phase converter

The leads torqued onto the capacitor terminals backwards is nice. The ground stud having a plastic cable clamp mixed in with leads is good too. A large capacitor bank should have bleed resistors as well, it's for your safety.

I don't wish to be critical but for your own safety I would be concerned about the cables that emerge from the cut end of what appears to be a metal flexible conduit without protection. They will chaff over the months with the motor vibrations. I endorse the other comment about a bleed resistor across the capacitor bank to discharge them when the beast is 'off'.

AWEM

What do you mean by backwards?

Good point, although the screw still conducts.

Well, remember that the capacitors are connected across the windings of the motors. I did think about it, I think that they discharge very quickly through the windings. I will double check that though.

I agree with you, I do want to buy a proper protection.

Unless you have some wiring removed for maintenance. Then you stick your paw across the isolated capacitor and zap!

Capacitors should not only have bleed resistors, they should have individual bleed resistors mounted directly on their terminals, through their own solder tags, placed below the main terminal. If the studs are long enough, they should even be nutted down separately so they never have to be removed.

Hm, if I have wiring removed, then they do not get charged.

I just verified it. I ran the RPC and turned it off and immediately (in perhaps 5 seconds) measured DC voltage across the caps. There was nothing.

I do not really mind it, but I do not see the big need in this application. As always, I am open minded.

There's also a problem known as "dielectric absorption", where a charged capacitor that's discharged then left disconnected will generate a charge of its own accord. This has delivered enough of a shock to make a nun swear (if not more).

You're running your capacitors on AC at a fairly low voltage, so they're pretty safe, whatever you do. My experience is more with HT DC laser PSUs at a few kV, where they're real killers if you're not careful.

But they are never disconnected from motor windings. I made sure of that.

They are basically directly connected to motor windings, they are wired into at the contactor/starter outputs along with the motor leads.

When the motors are running, there is induced voltage between 1-3 and

When the motors are not running, the caps quickly discharge through the windings. Any resistor that I would install would have resistance orders of magnitude less than the windings.

Well, 240V AC could charge them at peak voltage of what, about 380 volts? In other words, if the cap is disconnected (which would not happen in my system), when the charge is at the max, it could be charged up to 380 volts or there about. That's quite serious at 92 uF and 184 uF in two paralleled ones.

Or if the wire is bolted on counter clockwise so wants to fall off by itself.

Sure you are, so why not cut off the ground prongs on all your equipment. Ater all, it will never fail, so there's no need for ground anways.

It doesn't matter if the screw conducts if there's a fault current and the plastic melts off and you lose solid connection to that bolt.

This is the wrong mentality to be working on nonsense electrical projects like this.

Okay, I buy it. What value (ohms and watts) would you suggest?

| > The leads torqued onto the capacitor terminals backwards is nice. | | What do you mean by backwards?

Normally wires are wrapped around the terminal or fastener shank clockwise. What happens is that the tightening action pulls the wire into the joint, whereas to wrap it the other way will cause the wire to "squirt out." In your case you probably didn't see it because you have washers on both sides of the wire. BTW, with devices that have any kind of vibration, crimped lugs with proper insulation grip are the best way to do. The only time you'll see wire wrapped around a terminal in "legal" applications is for residential wiring, which is not likely to vibrate. Tying the wires together will also decrease the stress on the connections, which in your case will get really ugly when a wire breaks off. I have a terminal crimper from a seller in Seattle that has really good crimper sets to suit your need for a good price, considering what you get for your money.

Thanks. I have a cheapo crimper that actually does a decent job crimping (meaning that I cannot pull put the wire out). I will redo those leads in crimped ring terminal form. I also need to crimp on a few 6 gauge ring terminals, as well. When I do that, I will post new photos.

Thank you TMT. What do you think about the phase converter itself? I kind of like at least the concept of it, and want to fully clean up the implementation.

I have to second that :) I am enjoying the process. Keep up the good work! Glenn

openness to

While you are tidying it up, tighten up the clamp screws on the mains plug - at least one isn't done up

AWEM

One thing to consider is that a crimped terminal should be onto

I have seen crimp terminals designed for solid wires -- but these were not power-handling crimps.

Enjoy, DoN.

Absolutely, yes, I only use stranded wire for crimping.

I have been drifting farther and farther away from using solid wire. I pretty much use it only on breadboard or inside conduits, these days. The stuff you see on the caps is a remnant of old days and will be replaced soon.

For 6 gauge wire, I will try to use my hydraulic crimper.

Thanks for the tips.