How to reverse rotation on VR7F-8 compressor?

VR7F-8 compressor wires at the motor

VR7F-8 compressor wires at the motor

VR7F-8 compressor 7.5hp 80 Gallon single phase


Just bought a used compressor and at start up in rotates in the wrong direction. I tried reversing the input connections on the magnetic starter and that failed.

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Sep 03, 2015
VR7F-8
by: Doug in s.d.ca

Ah.

So it hadn't worked for you before...

Well, props to Champion for being cool about it, and thank you for sharing.

Sep 03, 2015
compressor
by: Poster

I talked to a few Champion Service guys and had one come over that was 2 blocks from my house to help me with start up. They were not going to charge me unless there was a problem and then it would be something like $120 an hour. The guy could not get it started with out pressing the magnetic coil. At that time we discovered that it was rotating in the wrong direction. He tried what was on a manual I had printed which said to reverse input connections on the magnetic starter. That did not work. He then tried another starter he had and that did not work. He said they would email me a more complete manual and try and figure it out. I got the manual the next day but it was the same one I already had. I set another appointment with them for next week to come over.

From another Champion service guy on the phone I found out the motor could be reverse at the motor. I looked on line and found what the number was for each colored wire coming from the motor. I rewired the motor from the using label that was on top of the motor as seen in my attached photo.

I called an Air Compressor repair company in Castro Valley. The guy there said to text him the pictures I had of the starter. I all so texted him a drawing I did of the current starter wiring and over the phone he said that I had the pressure switch wired wrong. I made the change and it started right up.

Sep 02, 2015
Mag starter redux
by: Doug in s.d.ca

YAY!
As I understand it, the way it was wired, there was no power to operate the mag starter.

Is the tech you talked to at Champion? If so, that's a big plus for this maker.

And that leaves the question: Does it run better?


Sep 02, 2015
It's running!
by: poster

I texted a drawing of the current wiring to a service guy I have been talk to on the phone and he said that I needed to move a pressure switch wire from L1 to L2 the other wire is hooked up to the back of the coil on top. It started right up. It is rotating in the correct direction and the auto oil shut off is wired in now.

So it was not creating a full circuit. I guess that the owner before might have had a complete circuit when it was hooked up to a buck booster. Thanks for all the help. I sure know more than I did before.

Sep 01, 2015
Mag starter
by: Doug in s.d.ca

Hmmm.

The starter CB (which is the reset) is seeing an overcurrent then. That suggests the motor wiring is either incomplete, (as in one or more wires at the motor need to be changed), or a short has somehow occurred.

I'd double-check the wiring for reverse, and if you can find nothing wrong, try it the way it was.

Bear in mind that it's possible a cap or something either came loose or went bad coincidentally witrh the re-wire.

You have the manual with the parts breakdown and wiring, correct?

Sep 01, 2015
switched rotation but won't start on it's own
by: Poster

Compressor will only start and stop by holding down the reset on the magnetic starter. The champion service guy said they could come out next week unless I can figure it out.

Aug 31, 2015
rotation
by: Doug in s.d.ca

---Which is why I asked if it was a replacement in the beginning.

So, what indicates to you that it's running backward?

Anyway, my concern would be if it were pressure lubricated (the R-15B pump, right?), but it's splash. So generally it doesn't care which way it turns.

However, I see that improper rotation can cause it to run hot, which probably means more water in the output.

It's supposed to run clockwise as viewed from the pump side with the flywheel at the back.

So, if it were mine, and running hotter than I'd like, I'd switch it. OTOH, I'd leave it if it WORKed for my purposes.

BTW, is the mentioned tech from Champion or?

Let us know what you decide and how it goes if you change it, please.

Aug 31, 2015
A concern on changing the rotation
by: Poster

The technician today said that it may be a concern to reverse the rotation if it's been running 12 years in the wrong direction question now is should I change the rotation and take the risk?

Aug 30, 2015
Motor
by: Doug in s.d.ca

Excellent.

Aug 30, 2015
I think I figured it out
by: Poster

I found online that the wires coming out of the motor are number one blue, number 4 yellow, number 8 red, number 5 black.

In the attached photo on the left is for counterclockwise on the right its for a clockwise it shows I need to switch the red and black wires.

I'll check with a technician tomorrow to verify.

Aug 29, 2015
rotation
by: Doug in s.d.ca

Right. Single phase doesn't care about reversing wires (operationally, anyway).

You should look under the cover (or on the nameplate) on the motor. IF it is reversible, you should find a wiring diagram on how to connect the motor wiring for reverse operation.

But, is this a replacement motor?

Anyway, good luck.

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Champion C15 compressor motor keeps tripping

by Kevin
(Australia)

I have just fitted a new run capacitor to my compressor motor. The unit is early 1980s.
The motor consistently runs for 7 seconds, loaded or not, before tripping.
_______________
Kevin, I'm happy to post this for you, though to make it easier for folks to help, knowing the make and model of the air compressor is good, as well as the motor voltage and HP. If you add that info as a comment here, you may get more specific responses.

Bill

Comments for Champion C15 compressor motor keeps tripping

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Jul 17, 2014
tripping
by: Doug in s.d.ca

OK. Just some background -

You've changed the cap: why? Are you sure it's the correct cap replacement?

I'm going to say you probably have a bad centrifugal switch.

Jul 10, 2014
More Info
by: Kevin

The compressor is a Champion C15. The motor is a Betts 240 volt 2000 watt.

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