Large motors and soft start

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Harold_V
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Re: Large motors and soft start

Post by Harold_V » Mon Jun 10, 2019 3:41 pm

Thanks, folks. I'm going to inspect the motor/generator to determine how it is connected. I'll report what I learn, but it won't be for at least one more day, as I will be away today.
I'm grateful for the education I am receiving.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

Harold_V
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Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: Large motors and soft start

Post by Harold_V » Tue Jun 11, 2019 6:54 pm

Ok, I'm back after a day in the "big city". We do a drive to Chehalis and Centralia to do our weekly shopping, but this time I had a little extra activity. Sunday evening, I was cleaning the lawn mower after Susan had mowed the yard. I'm not sure exactly what happened, although I think I hooked a toe on the edge of the concrete slab, the approach to the shop overhead doors. I did a quick dance trying to recover, but went down like a load of bricks. Due to circumstances I don't quite understand, my left arm got trapped under me, so I fell on my arm and face. Lots of "road rash" due to the broomed finish on the concrete, to say nothing of the black eye I now sport, thanks to driving my glasses in to the bridge of my nose. I also have a huge mouse above the eye, where my head made contact with the slab.

The worst part of this is it buggered my hand. It was swollen to about twice its normal size, so I finally relented and went to the emergency room, where it was X rayed. Staff at the hospital was concerned about the head wound, so I also underwent a Ct scan. The report on the scan indicated no bleeding on the brain, but the X ray wasn't necessarily conclusive. A splint was applied and I was sent on my way, with a very swollen and pretty much useless hand.

After leaving the emergency room, we travelled to Patio's home, so I could inspect the new controls he had designed and built for his Cazeneuve lathe. He did a remarkable job on both the design and manufacturing. Well done, Patio. You can be justly proud of a job well done.

Now, back to the motor generator.

The motor has nine leads. It is currently wired for the low voltage option, with leads 1-6-7 connected to the A phase, 3-5-9 connected to the B phase (that's the high leg) and leads 2-4-8 connected to the C phase.

The question was asked if the motor has six leads. As it has nine, but can be wired two different ways, is that equivalent to the six leads that were mentioned? From my vantage point, it appears that the coils are wired either in parallel (low voltage), or in series (high voltage). Am I correct? Do these wiring options allow for the star/delta starting method?

Again, thanks for the education.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

John Hasler
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Location: Elmwood, Wisconsin

Re: Large motors and soft start

Post by John Hasler » Tue Jun 11, 2019 7:27 pm

That would have to be a dual voltage delta. Star-delta isn't possible because there's no way to connect it star. See

https://www.efficientplantmag.com/2016/ ... -mistakes/

Part-winding start might be a possibility.

spro
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Location: mid atlantic

Re: Large motors and soft start

Post by spro » Tue Jun 11, 2019 9:01 pm

This is a great link, John H. It also shows the confusion when many pairs of leads are twisted together to a single for each. One needs dig deep to find that six wires are actually nine.
Back to priorities. Dear Harold, I am very sad about that accident and what it did. I can tell you what a trick of fate losing your hands and wrists becomes. Not totally lost and by good judgement you went to ER before the swelling was ...dang awful. I recall when falling off a ladder the forebone and wrist were smashed. That takes a huge toll to ability we need. Sure it healed and some bones are stronger but certain parts were never the same.
I don't mean to bore anyone, so skip past this,
I thought I was doing this right. The ladder was one I had used for years. I over reached, the ladder cocked and down I went. Instinctive to cushion the fall. Since..whatever. So I hope you heal well. Seriously, because it is.

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Bentworker
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Re: Large motors and soft start

Post by Bentworker » Tue Jun 11, 2019 11:38 pm

There are other ways of reduced winding voltage starting. Might be worth buying a motor control book and taking to your local motor rewind shop for other economical ideas.
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Jet 13x40 lathe.
Powermatic 1150 drill press.
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armscor 1
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Re: Large motors and soft start

Post by armscor 1 » Wed Jun 12, 2019 1:10 am

Hi Harold, wish my Partner would mow the lawn!!
Concur with John, you have a Delta/Delta motor wired for low voltage, Star Delta starting is out of the question.
From the photo I have taken of my milling machine motor it is similar to yours, all my motors in the shop are configured this way, 220 VAC 3 phase feeding through VFD's.
I hate to say it but a cheap Chinese VFD is probably the cheapest option unless the tariffs escalate.
I have 6 cheap Chinese and expect to get 4 to 5 years service before capacitors need replacing.
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Harold_V
Posts: 17738
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: Large motors and soft start

Post by Harold_V » Wed Jun 12, 2019 3:34 am

I'll try to get to the motor rewind shop in Centralia later this week. I'll see what they can offer in the way of soft starting for the motor.
Thanks for the included link in regards to how motors are wired. It's going to be quite useful for me.

I'll post again when I have learned more.

Thanks, guys.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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