7.5 HP Compressor Shutting Off - 3 Capacitor Testing & Identifying & Grease Fitting Question
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wyliesdiesels
Well-known member
Huh? Did u miss the part where the overload is tripping at 29a despite being set to 36a?
wyliesdiesels
Well-known member
I doubt the motor is overheating while pulling 29a.
My concern was that the heat exchanger was a very recent addition to your setup and the extra heat was cascading across the starter enclosure and warmer seasonal ambient temps were just making it worse to the point of now fualting.@wyliesdiesels : Makes sense, so the thermal cut off is shutting off the compressor and not the pressure switch. I keep saying multi-meter when I should be saying clamp on meter (old habits). I have a Klein CL800 which has the cap setting dial.
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Solid State Overload Relay: You mentioned checking, I have had the compressor for 3+ years now and haven't touched the settings dial, would that change? Assume I need to figure out how to test it to see if its failing. @micromind mentioned he has seen a number of them fail.
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Amp Check (Photo of where I am testing below): So I'll put my clamp on each leg and see what numbers I get. Plate shows 29-32 assume that it will be a bit higher when it starts up but should fall into this range after.
@mm08822 :
I put on the radiator to cool the air and moisture trap water separator as soon as I got the unit (a week later) It was the summer so temps were around 70s when I first started using it all the way till fall so temps were easily low 50s. No issues for 3+ years.
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We are in PA so weather varies, right now we are around the 60s in the day at night its still getting cold 40s. Why would adding an air cooler and water separator cause issues with the motor windings and bearings?
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Could you also touch on how air flow temp is impacting the compressor?
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Photos: Amp Test:
Even though solid state overloads are less susceptable to ambient temps, they do have operating temp limits - could just be impacting the life of the electronic parts if temps exceeded. It hasn't even been confirmed if the enclosure is in the path of the air flow.
As a few posts have already indiciated, if your o/l is set @position D = 38.5A and you are only 29+A when approaching 175psi, then I too agree your o/l block is bad. These are rated as Class 20 overloads, so they will trip in <20secs @ 600% of trip setting. You are not even at 100%.
Remove each one and see if anything is obvious - just 2 screws per position. A new set (#H2014B-3) is <$50.
micromind
Well-known member
My concern was that the heat exchanger was a very recent addition to your setup and the extra heat was cascading across the starter enclosure and warmer seasonal ambient temps were just making it worse to the point of now fualting.
Even though solid state overloads are less susceptable to ambient temps, they do have operating temp limits - could just be impacting the life of the electronic parts if temps exceeded. It hasn't even been confirmed if the enclosure is in the path of the air flow.
As a few posts have already indiciated, if your o/l is set @position D = 38.5A and you are only 29+A when approaching 175psi, then I too agree your o/l block is bad. These are rated as Class 20 overloads, so they will trip in <20secs @ 600% of trip setting. You are not even at 100%.
Remove each one and see if anything is obvious - just 2 screws per position. A new set (#H2014B-3) is <$50.
Lol......Now that I can see one up close, it is indeed 38.5, I thought I read 36.5
@mm08822 took out the "23.5 - 38.5 Amp Fast Trip Heater Packs" They all look ok except for the far right one. I noticed a little bit of scorching on the plastic. No visible damage on the actual single pack by the screw. I did see a little pit on the plate that is inside, unsure if that's from the factory or what. Looks like those back to back plates (shiny silver and dull) float on top of each other. Photos attached.
Thoughts?
Thoughts?
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wyliesdiesels
Well-known member
looks like you had a bad connection which was heating up causing arcing. this could cause a trip if the motor was not getting enough voltage thru that overload
@wyliesdiesels Took some time to check all the connections before pulling. Including my 2 hot wires and the copper one and bottom hots to the motor, all tight. The gold connector where the screw goes into isn't that dark, think the photo looks a bit worse. But that plastic burning is heat related for sure. Any ideas what to check?
Here is another shot of the heater pack. Still not sure if that is normal and not a big deal.
Here is another shot of the heater pack. Still not sure if that is normal and not a big deal.
ALLFAST
Well-known member
Lots of good information being shared here!Hi all, I have a 80g 7.5 NorthStar compressor 1 phase w/ mag starter (sold via northerntools). I have had it for about 3+ years. I probably have run it maybe 80-100 hrs total. Weekend warrior but occasional sandblasting and grinding under the car. Anyways the compressor started shutting off before hitting its 175 psi target. It turns on at (0-150psi and off at 175psi)
Action/Question 1:
I replaced the pressure switch as per tech support and it wasn't the problem. Figured it was something electrical so decided to check the capacitors on the Baldor motor. Can't find wiring diagram online. Motor is a 36LYH282 model. It has 3 capacitors, sure enough one of them is out of spec with the microfarads (uf) printed on it. This capacitor has 2 soldered 10k resistors, and I am not sure if those resistors would cause my multi-meter test result numbers to be incorrect?
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This capacitor is the same as one of the other ones. Baldor EC1216C06. Since I have 3 capacitors, I am assuming 1 is start cap, 1 is the run cap, and the other the thermal cap? Anyway to figure which one of these it is?
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Is it normal for capacitors to go bad? The center one is showing 456uf and should be 216-259uf. My multimeter has the uf setting to test.
Question 2:
I thought I was going nuts but I think this Baldor motor has grease zerks on it. I found a diagram of it on their site (https://www.baldor.com/api/products/L1509T/drawings/36LYH282). Are we suppose to grease these? Nothing in the manual about that.
I would add if your unloader has a diaphragm/gasket, if it’s failing ( hairline cracks, embrittlement, pinholes, etc) weird things are going to occur.
Check if any excess moisture/condensation/water is clogging up the lines to the unloader/pressure switch…This can cause issues as well.
Also inspect the copper lines for any pinholes/cracks (especially near bends) and inside the fittings for damaged ferrules (if so equipped) ; also check for debris clogging up any of the aforementioned places-any chunks of dirt, rust flakes, etc, will cause issues.
I zoomed in on the rightmost heater pack shown separately and next to the screw looks cracked/melted.
Maybe it was loose for some time, started heating up and eventually bound up. So when you went to remove it, the screw felt tight.
Re-assemble with a very light drop of mineral oil/lube just to keep the threads from damaging each other. Maybe swap position of the right one with another.
Maybe it was loose for some time, started heating up and eventually bound up. So when you went to remove it, the screw felt tight.
Re-assemble with a very light drop of mineral oil/lube just to keep the threads from damaging each other. Maybe swap position of the right one with another.
Damn, I'm going to have to pull them out tomorrow and double check. Don't see that in the photo when i zoom, weird. Eaton used the crappiest screws i have ever seen in these.I zoomed in on the rightmost heater pack shown separately and next to the screw looks cracked/melted.
Maybe it was loose for some time, started heating up and eventually bound up. So when you went to remove it, the screw felt tight.
Re-assemble with a very light drop of mineral oil/lube just to keep the threads from damaging each other. Maybe swap position of the right one with another.
rlitman
Well-known member
They look to me like they're PoziDriv. A philips driver in a pozi screw is going to make the screws feel crappy, but using the wrong kind of screwdriver could also explain these weren't tightened properly before.
That could easily have been the case at the factory. The top right connection even looks bent/rotated down so the o/l block screw didn't engage the threads other than just the leading taper of the screw mate up with the hole. (Red arrow)
This would explain the burn marks and pitting to the right of the screw hole while the left side is clean b/c of no contact.
See if that can be bent back to square (rotated in opposite direction of red arrow) while restraining the fixed end or better yet removing first from plastic base. Chase the threads afterwards before re-assembly with the heater block.
@mm08822 good eyes! I took out the suspected breaker today to look at it again. It's not actually cracked or broken. Must have been a compression artifact in the photo. It does have a bit of grey burn spots on the screw side though.
Hopefully tomorrow I'll get home early enough to run some more tests.
Hopefully tomorrow I'll get home early enough to run some more tests.
Hi guys, so **** news. I replaced the complete mag starter box. Connected everything back and set the two dials on the heat packs to the same specs as the old ones. So first startup, I thought I saw a bit of dust come out of the motor starter (top section). But I wasn't sure. Anyways filled the compressor up all while watching my clamp on meter. Amps were the same as before started at 22 climbed to a little over 29. Then shut off the compressor auto-start and went to work outside.
Came back in when I was almost fully out of air. Hooked on my clamp meter and then started, and the fire works flew. That same outside breaker arched for sure. I waited like a minute and watched the clamp meter, still 22-23 then shut it off.
So I am assuming the problem isn't the heat packs. Picture attached is from a video I was taking.
Lost as to what's next.
Came back in when I was almost fully out of air. Hooked on my clamp meter and then started, and the fire works flew. That same outside breaker arched for sure. I waited like a minute and watched the clamp meter, still 22-23 then shut it off.
So I am assuming the problem isn't the heat packs. Picture attached is from a video I was taking.
Lost as to what's next.
I think you are introducing too much variables to trouble shoot all at once. did you shorted out something while changing out that box ? or changing something in that box ? that arcing might not be your original problem.
if it was me.... I would isolate the troubleshooting...
like when the issue happens... ?
looking at your pressure switch, you only have one leg used. a white wire and a black.
is there electricity when the issue happens at that pressure switch.. at the wire that goes to the starter/breaker/heat packs ? and at the wire that goes to the capacitors. (black wire ??? from guessing).... basically that pressure switch is breaking only breaking one of the two legs of the 240V not both according to your pic even though it seems it can do 3 sets of wires...
micromind
Well-known member
Is the contactor rated at 7.5HP 240 volts single phase?
If it's rated at 7.5HP 3 phase, it's too small and will spark when the motor starts.
Also, is the coil 240 volts? A lot of them are 120 volts.
If it's rated at 7.5HP 3 phase, it's too small and will spark when the motor starts.
Also, is the coil 240 volts? A lot of them are 120 volts.
@mm08822 exact same model and replacement part from dealer, they flipped the bill so I was like ok.
@dogdog All the wiring is original, so how the factory set things is up is how its been running (3+ yrs). The pressure switch comes into the mag starter and has 3 wires. Two hots and one ground (see pic below I put the green). It's green and threaded into the box at the bottom left corner. Originally, tech support thought it was the pressure switch, so a new one was installed. Then, thanks to the guys here, we noticed the heat pack had arched. The new mag switch box, which has new heat packs, also arched today. So that wasn't the problem. I haven't tested the power from the new pressure switch.
@micromind this is how it came stock and has worked for 3 years.
After installing the new mag starter box. I put the probes on each leg of the motor starter (L1 and L2) I had power as expected. So your saying I should test for power at the pressure switch hots. I can do that tomorrow. I hate throwing parts at things, I want to find what is wrong so I can get back to doing my work lol.
(pic)New box installed. Arching occurred again on the far right heat pack as I can see some greys.
@dogdog All the wiring is original, so how the factory set things is up is how its been running (3+ yrs). The pressure switch comes into the mag starter and has 3 wires. Two hots and one ground (see pic below I put the green). It's green and threaded into the box at the bottom left corner. Originally, tech support thought it was the pressure switch, so a new one was installed. Then, thanks to the guys here, we noticed the heat pack had arched. The new mag switch box, which has new heat packs, also arched today. So that wasn't the problem. I haven't tested the power from the new pressure switch.
@micromind this is how it came stock and has worked for 3 years.
After installing the new mag starter box. I put the probes on each leg of the motor starter (L1 and L2) I had power as expected. So your saying I should test for power at the pressure switch hots. I can do that tomorrow. I hate throwing parts at things, I want to find what is wrong so I can get back to doing my work lol.
(pic)New box installed. Arching occurred again on the far right heat pack as I can see some greys.
I think you are back to the same problem. Those blocks look skewed.
Loosen the copper jumpers on the load side of the contactor so they are not restrained.
Remove each heater block. Re-install each, making sure top screws are actually threading into each copper "lug" beneath the screw.
If the right block is screwed up, get a good one from the old.
Once o/l connections are certain, check each copper jumper position in the contactor lug. Adjust as needed with a couple of needle nose. Tighten contactor lugs.
Spark it up.
Loosen the copper jumpers on the load side of the contactor so they are not restrained.
Remove each heater block. Re-install each, making sure top screws are actually threading into each copper "lug" beneath the screw.
If the right block is screwed up, get a good one from the old.
Once o/l connections are certain, check each copper jumper position in the contactor lug. Adjust as needed with a couple of needle nose. Tighten contactor lugs.
Spark it up.
walta
Well-known member
Seems clear from the burn marks the overload vented the fireball.
I can’t think of a reason the same right side overload would open both times. If there are no ground faults the current flow in all 3 overloads must be equal. If there were a ground fault the same current would flow thru the center and the right overload.
My wild guess is if you dissemble the motor and post photos of the motors winding, they will not look like clear varnish on copper but will look blackened with cracked varnish. If so that motor is trash.
Walta
I can’t think of a reason the same right side overload would open both times. If there are no ground faults the current flow in all 3 overloads must be equal. If there were a ground fault the same current would flow thru the center and the right overload.
My wild guess is if you dissemble the motor and post photos of the motors winding, they will not look like clear varnish on copper but will look blackened with cracked varnish. If so that motor is trash.
Walta
rlitman
Well-known member
Megger testing of the motor would prove that out quickly.
wyliesdiesels
Well-known member
Thats because the pressure switch runs the coil in the starter. Dont need 2 sets of conductors on the pressure switch
wyliesdiesels
Well-known member
It only needs to switch 1 leg because again, its operating one side of the coil in the starter
wyliesdiesels
Well-known member
Testing the pressure switch is gonna be a little different than testing for power because you are only switching 1 leg.
The way to test the pressure switch is to see if you have continuity between input/output terminals when the switch is closed. Make sure to turn off the power going to the compressor first
I changed out the breaker today at the subpanel (50 amp). Just to rule out a failing breaker. Turned it on, and again sparks flew. I put two amp clamps on the lines going to the electric motor, this time I was expecting the sparks and filmed. Now for a split second on the amp clamp I saw 55.12. This is on turn on, what do you guys think about that? Looking at yesterdays video I also saw a large jolt, think the clamp showed 105 briefly from the wire coming from the sub panel into the mag starter.
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@mm08822 I agree first thing I saw when I got the box was they weren't exactly straight. But then I am thinking why would that be an issue? So long as the terminals are correctly on and tight, and they seem to be.
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@walta the 100k question is what is causing the fireball
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@wyliesdiesels Testing right on pressure switch terminals. Ok so power to the compressor off, and power to the pressure switch off. No continuity. When I turn the switch to auto, I have continuity. Tested the old pressure switch and same results. Continuity when it is on automatic mode. Normal?
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Any other testing?
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@mm08822 I agree first thing I saw when I got the box was they weren't exactly straight. But then I am thinking why would that be an issue? So long as the terminals are correctly on and tight, and they seem to be.
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@walta the 100k question is what is causing the fireball
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@wyliesdiesels Testing right on pressure switch terminals. Ok so power to the compressor off, and power to the pressure switch off. No continuity. When I turn the switch to auto, I have continuity. Tested the old pressure switch and same results. Continuity when it is on automatic mode. Normal?
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Any other testing?
Yes, op have 3 caps 2 in parallel and one shinny one for run cap right. Sort of in a two in one configuration. That coil is not just a start, it’s also a run coil. When the (pressure) switch breaks contacts ? It stops the motor right. Otherwise if it is just a start coil it would have kept running.
The suggestion is for the op to isolate the components to trouble shoot. Unfortunate some steps it would have to be live circuits while the issue is happening.
Might be the motor back emf or just bad motor. I won’t know.
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… it’s a precursor statement says to test the incoming leg and out going leg against the other referenced unsWitched for 240v. “Not across” the switch pe se. Don’t know if I explain it right.
An non contact beeping should do the trick as well
Start-up inrush.....can expect anywhere from 4-8x motor fla. Amounts are not surprizing.
If you haven't confirmed all of the mentioned connections are correctly made and tight, "seeming" and "being" are not necessarily the same. I don't know why you want to shoot the fly with a shotgun instead of using a fly swatter. You're just throwing parts at it - free or not.
Remove the copper jumpers from the contactor output side and connect the motor directly to it. Run it. What happens now?
micromind
Well-known member
If sparks are coming from the overload relay, it's bad. Even if it's new, it's still bad.
The overload relay needs to conduct the full current of the motor plus the starting current without any type of spark.
The only sparks will be inside the contactor though you might see a small blue flash when it turns on and off.
As noted above, remote the bare jumpers from the contactor and overload relay, connect the motor directly to the bottom of the contactor turn it on and see what happens.
The overload relay needs to conduct the full current of the motor plus the starting current without any type of spark.
The only sparks will be inside the contactor though you might see a small blue flash when it turns on and off.
As noted above, remote the bare jumpers from the contactor and overload relay, connect the motor directly to the bottom of the contactor turn it on and see what happens.
wyliesdiesels
Well-known member
during startup there is whats called in-rush current. in-rush current can be 4x-8x FLA on nameplate.
However, most meters cannot read this current properly and you will get wild readings. the meter needs to be specifically designed to read in-rush current like a fluke 376
can you post a video?
yes that is normal. you want continuity when PS is closed/on and no continuity when its open/off
I need to see where the fireball is coming from first before i can figure out what else to test
So just to refresh. New mag starter installed. Two blue dials on the heat pack set to previous settings. The heatpacks are H2014B and set to M (manual) and D. Today started up twice to test. Both tests, HUGE amount of sparks, more then the old one. Both times. First time, sparked but tank filled and pressure switch set point hit of 175psi. Second time, sparked and tank psi got to about 172 and the thermal overload kicked on and shut it off. Pressure switch air release didn't kick off obviously. It did kick off when I turned it off. I can see arching on the far right heat pack, more then the old box.
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@mm08822 I checked all the connections, but I will double check tomorrow. You're saying to bypass the heater packs. What could we hope to learn from that? That would bypass the thermal protection that the heat packs provide right? Thinking about that, could the power coming from the subpanel be causing any issues?
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@micromind Damn what are the odds. This one for sure sparks way more then the old one as I mentioned above.
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@wyliesdiesels Ok, yeah my Klein def can't do rush in current.
Here is a video of the second time I tried this today. Don't mind me talking I was trying to keep mental notes.
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Forgot this is what the bypass would look like?
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@mm08822 I checked all the connections, but I will double check tomorrow. You're saying to bypass the heater packs. What could we hope to learn from that? That would bypass the thermal protection that the heat packs provide right? Thinking about that, could the power coming from the subpanel be causing any issues?
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@micromind Damn what are the odds. This one for sure sparks way more then the old one as I mentioned above.
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@wyliesdiesels Ok, yeah my Klein def can't do rush in current.
Here is a video of the second time I tried this today. Don't mind me talking I was trying to keep mental notes.
Forgot this is what the bypass would look like?
micromind
Well-known member
I don't know what the odds of 2 in a row failing, whenever I get called to a failed starter of that type, I replace the entire overload block, usually with an Allen Bradley one, if it'll fit.
Removing the 3 bare wires and connecting the motor directly to the bottom of the contactor will bypass the overload block and will tell us if the source of the sparks is the O/L block or something else.
Removing the 3 bare wires and connecting the motor directly to the bottom of the contactor will bypass the overload block and will tell us if the source of the sparks is the O/L block or something else.
wyliesdiesels
Well-known member
looks like the sparks are coming from the overload block. move motor wires to T1 and T3 (first and second lugs) at bottom of contactor.
Chevron Black Pearl is one we sell often for motors.