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Worked a bit on wiring for my phase converter

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from my webpage:

I spent one more evening finishing up the electrical system. I made sure that I have very solid ground. For that, I added a grounding terminal to my subpanel, and also inserted a length of solid copper wire into the incoming conduit for better contact. (I do not trust contact of conduit with the subpanel, too much).

I added a grounding terminal to the phase converter and terminated several grounds there: incoming ground, ground for the motor, for all electrical boxes, and outgoing ground are all connected in one block.

All screws on the contactor were tightened. Signal connections for the contactor were made with blade terminals. Everything was well screwed down with screws.

You can see that the input box (the top shiny electrical box) has the following: incoming wire, convenience outlets, and an on/off switch. The on/off switch does not turn the motor on: it is completely inadequate for this task. Instead, it turns the contactor on and off, and the contactor s rated for 75A, 10 HP at 240V.

The bottom electrical box is the output box and has a four terminal block: three legs (numbered 1-3 from bottom up) and the top terminal is for ground. I have a child at home and do not want to cause any trouble.

I have not yet enclosed input wires into a flexible conduit.

i
Reply to
Ignoramus20106
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My suggestion would be to learn about "liquid tite" flexible conduit. I use this for all wiring on machines where the standard S cord does not work well.

Another point that nobody has mentioned yet - you have a large number of tie points and wiring devices that are installed directly on particle board.

In most cases wiring is installed in steel enclosures (boxes, panelboards, etc) because the steel is non-flammable and can resist fire and arcing for a fairly long time before it heats up enough to ignite whatever it is mounted on.

For example, a fire marshal will frown upon an installation where the box *cover* has been omitted or removed because any arcing inside the box can then easily ignite surrounding flammables.

When improving and upgrading your phase converter (as we all know these are ongoing projects) you might want to begin putting all the wiring and components inside proper enclosures. It would be a great deal more fire-resistant if anything went wrong.

Jim

Reply to
jim rozen

I'll check it out. Is that conduit with metal inside and grey plastic outside?

That's correct.

Thanks. I am looking very hard for a decent welder at a great price, so far I am not finding anything, but when I find one, I may well redo the enclosure.

i
Reply to
Ignoramus6208

Hi i, I didn't see any overload equipment listed on your "buy" list but did see this drawn on the metalwebnews site. Even though I'm no electrician please tell me you do have an overload installed, I'll sleep better. dennis in nca

Reply to
rigger

Rigger, good question. I have not yet found a cheap good 10 HP overload. I have a 7.5 HP overload, but it is not suitable for 10 HP so I am selling it. I'll see that guy again and will check if he has

10 HP overloads. i
Reply to
Ignoramus6208

Don't bother - commercial steel electrical enclosures are amazingly cheap. They're build in mass quantities. Take a trip to a local electrical supply house.

Jim

Reply to
jim rozen

Thank you. What are these enclosures like. To be honest, I do not have a mental picture of what you are talking about.

i
Reply to
Ignoramus19023

This page has a pretty good selection of what's available for NEMA 1 boxes. NEMA 1 means the box provides mechanical protection but no protection from dust, liquids, corrosive atmospheres, etc. Other NEMA classifications will cover these hazards, at more cost, of course.

Ned Simmons

Reply to
Ned Simmons

Oops, forgot the link...

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Ned Simmons

Reply to
Ned Simmons

A-ha, I got it. Thank you.

i
Reply to
Ignoramus19023

What's really neat about lots of enclosures is the back plate. This is a flat plate in small sizes, flat plate with stiffeners in larger sizes, mounted on studs welded inside the enclosure. You do most of your layout, mounting, and wiring of heavier components on the back plate on the bench, punch the holes in the door for your control components (see the Greenlee thread), then mount the back plate, mount your control stuff (switches and lights) on the door, then wire it up. Be sure to include a good loop of wire at the hinge to allow easy closure without binding the wire or its strain reliefs.

This is where it pays to design the complete box including wiring before you start punching holes. I usually have the box built to my design with all holes already burned in. Of course, I'm a chemist and controls guy, so I have an EE look at it before I order the box.

I've used a similar process (on a far smaller scale) at home, except I'll re-use stuff instead of buying everything new.

Pete Keillor

Reply to
Pete Keillor

Very nice. I will definitely keep it in mind.

i
Reply to
Ignoramus19023

Ive got 4 brand new NEMA boxes, about 10" deep, by about 13" wide, by about 18" long. I check this weekend on actual dimensions.

Need one?

Gunner

Liberals - Cosmopolitan critics, men who are the friends of every country save their own. Benjamin Disraeli

Reply to
Gunner

Depending on the size of a 3-phase motor I'll need to convert with maybe I can get one if there is a spare.

Do you know the total HP - is there one or more motors ?

Martin

Reply to
Martin H. Eastburn

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