gary huston

Single phase motor wiring help

13 posts in this topic

Hi guys, 

I hope someone can help me out. I'm building a belt grinder and have acquired a 230v 2hp 2800rpm single phase motor. Although it runs fine I would like it to run in the opposite direction and add an on/off switch. I took the cover plate off to see what was what and although i'm no expert the way it's wired looks odd. I don't know why it just seems unlike what i have seen before. I thought the cap leads should go to W1 & V1 not U1. Can someone cast an eye over it and just confirm it looks ok and maybe let me know what to swap to change direction. I think I just need to swap the jumpers from W2-U1 to W2- U2 and U2-V1 to U1-V1. But as I say i'm no expert! Much appreciated, I attach some photos of all I know!

 

 

 

motor wiring.jpg

IMG_0056.jpg

IMG_0057.jpg

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the details in the cover are for 3 phase so ignore them, you could contact the makers but it looks chinese

on most you would change the 2 links from vertical to horizontal and move the neutral wire to the bottom

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You did not say what kind of a starter circuit this motor employ's, but I am going to assume it is capacitor start. What you need to do is reverse the wires that go to the auxiliary circuit.  The Aux. circuit is the starter winding circuit, once the motor is kick started the primary winding's do not care which way the motor rotates.  I have copied a drawing which I hope transfers when I post this.  The problem you have is finding the Aux circuit wiring.  This drawing for a capacitor start motor says that V1 & V2 are the terminals you need to reverse.  Don't change the metal links from vertical to horizontal you will short out the primary line and get to see a nice bright light for a short time.

 

Cap Start.jpg

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I didn't mention that it's a capacitor start as I thought that was obvious from the photo with the capacitor leads marked. I have no idea if there is an aux circuit as there are only four wires coming from the motor and nothing else. I guess I'll just leave it as it is and put the motor on the other side of the machine.

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2 minutes ago, gary huston said:

I guess I'll just leave it as it is and put the motor on the other side of the machine.

As Gary cuts the Gordonian Knot....

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Is that easier than asking at a local motor repair place?  I had an ancient motor for my powerhammer and took it down to my local place and they had is figured out in a couple of minutes and didn't even charge me!

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If only we had somewhere like that here. No one these days knows how to repair anything, they just say "it's had it" and put in a new one. I doubt if I could find anyone with enough knowledge round here. We don't have "repair" shops.. 

It's no big deal, it works as it is and all I need to do is put it on the other side so it will still do the job. Thanks anyway.

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20 minutes ago, gary huston said:

I didn't mention that it's a capacitor start as I thought that was obvious from the photo with the capacitor leads marked. I have no idea if there is an aux circuit as there are only four wires coming from the motor and nothing else. I guess I'll just leave it as it is and put the motor on the other side of the machine.

Sorry about that, I forgot about the labels you had put on the drawing while I was on line looking for information on the starter circuit.  There is a way to find the starter circuit without the internal labels in place but it takes an ohm meter and some disassemble of the motor (I think).  If you know anyone that does Heating/Air-conditioning repair they may be able to give you some pointers. Although mounting on the other side of the grinder works for me too.

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18 hours ago, JHCC said:

As Gary cuts the Gordonian Knot....

Ha ha! I'm a great believer in Ockham' razor...

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you mean occams razor

this is more likely capacitor run than start, better quality ones have a centrifugal switch on the armature or a timer in the box, this one being chinese will probably not have the internal switch and there is no timer in the box but to be sure you would need to open up the motor

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19 minutes ago, the iron dwarf said:

you mean occams razor

this is more likely capacitor run than start, better quality ones have a centrifugal switch on the armature or a timer in the box, this one being chinese will probably not have the internal switch and there is no timer in the box but to be sure you would need to open up the motor

No, I mean "Ockham's razorLatinlex parsimoniae "law of parsimony") is a problem-solving principle attributed to William of Ockham (c. 1287–1347), who was an English Franciscan friar, scholastic philosopher, and theologian."

 

im not going to bother mucking about with it, it works so I'll just mount it on the right. It will probably be better that way as I'm primarily right handed so much easier to use the switch.

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42 minutes ago, the iron dwarf said:

you mean occams razor

 

20 minutes ago, gary huston said:

No, I mean "Ockham's razor

Technically, either is correct. English spelling wasn't standardized in William's time, and "Occam" is probably a latinization of "Ockham".

At least, that's the simplest explanation that fits all the facts.

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Gary,

Looking at the photo you posted and the labels you added, it looks as though the middle terminal on the bottom row is labeled "Black from motor".  I don't see a wire there but that might just be due to the angle of the photo.

If it is indeed from the motor, it sounds like the start circuit is connected on the first and second terminals from the left on the bottom row.  Reversing them will reverse the polarity, which should reverse the direction of the motors rotation from it's current direction.

 

 

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