WAYNE compressor electrical woes

[hotrodA]

Although I’ve been active on the HAMB for 20 years, I cruise over here when time permits.
Here’s my problem.

I have an older Wayne compressor that has been a work horse for 15 plus years for me.
Model 6885-SH, two cylinder, two stage. Used when I got it.
It’s running a 5 hp, 240V, single phase magnetic start motor, with a disconnect switch with two 20A fuses. That is off a main panel with a 30A breaker.

It just started blowing one (the same) 20A fuse on one leg of the disconnect switch.
It does this at random intervals. Replace the fuse, it runs like it always has in the past. Until the fuse goes.

It was suggested by the owner of the electrical supply here that the unloader valve may be sticking, and the resultant head pressure is causing the motor to kill the fuse on start up.

Any input or suggestions?

Know where I can get a manual with parts diagram?

Thanks!

 

[wyliesdiesels]

If this is a true 5hp compressor, the FLA is gonna be more than 20a. So the 20a fuses are too small

Can you post a pic of the motor nameplate?

Since you have a magstarter, the fuses are pointless.

What is the size of the heaters in the OL relay on the mag starter?

 

[mm08822]

When does it blow the fuse, on initial startup or once running for some time?

If on startup, does the unloader valve release a short blast of air when comp turns off? if not, that is at least one problem.

 

[nadogail]

When does it blow the fuse, on initial startup or once running for some time?

If on startup, does the unloader valve release a short blast of air when comp turns off? if not, that is at least one problem.

If there is no "Air Squirt" it isn't unloading.

 

[RPH]

If this is a true 5hp compressor, the FLA is gonna be more than 20a. So the 20a fuses are too small

Can you post a pic of the motor nameplate?

Since you have a magstarter, the fuses are pointless.

What is the size of the heaters in the OL relay on the mag starter?

This is where the copper tube replacements come in. Always shocked to open a box and find that. Same answer, everywhere, too much work to replace fuses. So we moved to copper and never have the problem! I just duly report and advise upper management at the plant of poor choices. Then let the legal team back at my plant handle it.

 

[hotrodA]

Thanks for the response! I started it again and upon shutoff, can hear no air release. Check that next.

Anybody have specs or diagram on this pump?

 

[hotrodA]

If this is a true 5hp compressor, the FLA is gonna be more than 20a. So the 20a fuses are too small

Can you post a pic of the motor nameplate?

Since you have a magstarter, the fuses are pointless.

What is the size of the heaters in the OL relay on the mag starter?

Thanks, did not know that about the mag starter and fuse,
Had the surplus disconnect and used fuses to make it operable.
Don’t know about heaters

 

[hotrodA]

When does it blow the fuse, on initial startup or once running for some time?

If on startup, does the unloader valve release a short blast of air when comp turns off? if not, that is at least one problem.

No air noise upon shutoff.
Don’t know when it blows fuse. Intermittent use.

 

[dave*99]

Looks like 20A fuses are a bit low based on the motors specs.

 

[mm08822]

Your motor's full load amps are 24A. So 20A fuses would be right on the edge of blowing. Then add the start-up under load b/c the unloader valve failed and fuses will surely be popping.

Put in 30 - 35A time delay fuses.

Remove the small tubing (~1/4") from the compressor head connecting to the pressure switch and verify not blocked. With tubing still removed, look into the open port on the pressure switch and verify not loaded up with debris/oil. Use q-tip/pipe cleaner to rod it out if you don't have any compressed air available. Worst case, you need to remove ps and open it up to further clean out. Put it back together and give it a try.

 

[hotrodA]

Your motor's full load amps are 24A. So 20A fuses would be right on the edge of blowing. Then add the start-up under load b/c the unloader valve failed and fuses will surely be popping.

Put in 30 - 35A time delay fuses.

Remove the small tubing (~1/4") from the compressor head connecting to the pressure switch and verify not blocked. With tubing still removed, look into the open port on the pressure switch and verify not loaded up with debris/oil. Use q-tip/pipe cleaner to rod it out if you don't have any compressed air available. Worst case, you need to remove ps and open it up to further clean out. Put it back together and give it a try.

Thank you!

 

[wyliesdiesels]

Post a pic of your mag starter showing both the contactor and the overload relay.

You really dont need a fused disconnect

How far away is the panel and is it within sight of the compressor?

 

[hotrodA]

Post a pic of your mag starter showing both the contactor and the overload relay.

You really dont need a fused disconnect

How far away is the panel and is it within sight of the compressor?

Panel is three feet away.
What would you recommend for a disconnect or start/stop switch?
is the contactor and relay accessible by pulling the cover?
Thanks!

 

[Norcal]

Panel is three feet away.
What would you recommend for a disconnect or start/stop switch?
is the contactor and relay accessible by pulling the cover?
Thanks!

Get rid of the disconnect if it is 3' from the panel the breaker can serve as the disco, and a start/stop switch such as used with 3-wire control cannot be used with a compressor, the pressure switch is what needs to control the operation. The starter internals will be exposed by removing the cover.

 

[wyliesdiesels]

Panel is three feet away.
What would you recommend for a disconnect or start/stop switch?
is the contactor and relay accessible by pulling the cover?
Thanks!

Don’t need a disco at all. Ditch it

As said above The pressure switch would be the controller for on off. Does your pressure switch have an on off switch on it? If not just use the breaker

 

[hotrodA]

Don’t need a disco at all. Ditch it

As said above The pressure switch would be the controller for on off. Does your pressure switch have an on off switch on it? If not just use the breaker

Thanks! No on/off switch on the pressure switch.
Just thought that I had to have a separate on/off switch.

 

[dave*99]

Thanks! No on/off switch on the pressure switch.
Just thought that I had to have a separate on/off switch.

Not even a mechanical arm on the side of the pressure switch that says auto and off? Those work by blocking the movement of the switch mechanism effectively turning the compressor off.

 

[wyliesdiesels]

No requirement for that. Disconnect only needed for servicing but breaker qualifies in your situation

 

[hotrodA]

Nope. SquareD pressure switch. Don’t remember if was on the tank, or came with the compressor pump. Probably contributed to me Wiring in the fused disconnect.

 

[hotrodA]

Thanks, everyone!

 

[hotrodA]

Not even a mechanical arm on the side of the pressure switch that says auto and off? Those work by blocking the movement of the switch mechanism effectively turning the compressor off.

Nope. Just a Square D pressure switch. Don’t remember if it came on the tank or with the pump.

 

[hotrodA]

No requirement for that. Disconnect only needed for servicing but breakers qualifies in your situation

Thanks!

 

[wyliesdiesels]

Nope. SquareD pressure switch. Don’t remember if was on the tank, or came with the compressor pump. Probably contributed to me Wiring in the fused disconnect.

Post a pic of the PS