Single Phase Motor tripping overload

[JB86]

Hello,
I have a customer that has a 10HP single phase 230 volt motor on a dust collector that trips out the overload that is built into the motor (reset button on the side of the motor junction box). It trips out after about a half hour of running.
The voltage is good (between phases and phase to ground), amperage is 41 amps per leg and the FLA on the nameplate is 39.
The motor is 3 or 4 years old, and we can easily spin the motor shaft by hand with everything hooked up.
This is your mission if you choose to accept it.

 

[ptonsparky]

Dust collector. Clean the motor off. Make sure its fan is not broken. It is overloaded....by 2 amps.
What is amperage at the time of trip? Are the dampers properly adjusted?

 

[ptonsparky]

Are the run capacitors good?

 

[ptonsparky]

That will be $250. Send to...

 

[LarryFine]

Dust collector. Clean the motor off.

 

[synchro]

That must be some of that "smart dust".

What Is Smart Dust?

Smart dust refers to tiny sensors that suspend in the air and collect data from their surroundings, whether that be combat zones or the inside of a human body.

builtin.com

 

[hillbilly1]

Direct drive? Or belt drive? Most likely bearings have never been lubed, overloading the motor.

 

[MTW]

Hello,
I have a customer that has a 10HP single phase 230 volt motor on a dust collector that trips out the overload that is built into the motor (reset button on the side of the motor junction box). It trips out after about a half hour of running.
The voltage is good (between phases and phase to ground), amperage is 41 amps per leg and the FLA on the nameplate is 39.
The motor is 3 or 4 years old, and we can easily spin the motor shaft by hand with everything hooked up.
This is your mission if you choose to accept it.

Reduce the load by closing down the airflow at the outlet discarge damper or reducing the inlet blast gates on the system. This adjustment should be done with clean filters so that it is at maximum flow. As the filters get loaded and airflow reduces airflow will reduce and motor load will go down. They might have just replaced or cleaned the filters, increasing airflow load.

 

[__dan]

Exactly as above. Reducing airflow reduces motor load which reduces line Amps. throttling down the suction side is the easy way to do it.

Also, at 10 hp, it might have adjustable sheaves on the motor pulley (if belt drive). Adjust the sheaves to reduce pulley diameter and lower load.

If the sheaves are adjustable you would adjust them with the flow gate wide open.

 

[hillbilly1]

Reduce the load by closing down the airflow at the outlet discarge damper or reducing the inlet blast gates on the system. This adjustment should be done with clean filters so that it is at maximum flow. As the filters get loaded and airflow reduces airflow will reduce and motor load will go down. They might have just replaced or cleaned the filters, increasing airflow load.

Exactly as above. Reducing airflow reduces motor load which reduces line Amps. throttling down the suction side is the easy way to do it.

Also, at 10 hp, it might have adjustable sheaves on the motor pulley (if belt drive). Adjust the sheaves to reduce pulley diameter and lower load.

If the sheaves are adjustable you would adjust them with the flow gate wide open.

Sounds like this just started, and was running fine before. So unless someone messed with it, that’s not the problem.

 

[__dan]

Sounds like this just started, and was running fine before. So unless someone messed with it, that’s not the problem.

Running without ductwork or changing the ductwork, the ductwork reduces airflow and the motor load down to the rating. I would not expect the regular operator to know this and damper down manually. If it has sheaves they are normally adjustable for this.

39 FLA single phase is a 7.5 hp motor, not 10 ???

 

[ActionDave]

....The motor is 3 or 4 years old, and we can easily spin the motor shaft by hand with everything hooked up.
This is your mission if you choose to accept it.

I agree with checking the caps and blowing out the dust.

Depending on how many hrs the motor has run it may be time for new bearings. Old sealed or shielded bearings that have less grease than new ones spin easier.

 

[herding_cats]

The overload protection is sensitive to both heat and current load. It will trip on both, or individually. Blow out the fan, screens or covers.

 

[JB86]

New item by Josh Bishop

photos.app.goo.gl

Pic

 

[JB86]

Thanks for all the feedback!
I shared a pic of the nameplate and here is some more info.

The motor appears to be pretty clean. The dust collector sits outside and the motor is not enclosed in any part of the dust collector so it stays in a relatively dust free area. The motor sits on top of the dust collector and is totally exposed to the great outdoors.
It has been running flawlessly since it was installed and just started tripping the overload a day or 2 ago.

I'll ask him if they have changed anything recently (as far as cleaning it, adding any duct work or machines, or changed their production process).
I'll also ask if they have done any preventative maintenance on the unit (such as greasing the bearings).
It is a belt drive.

All the capacitors visually look fine, I know that's not a great indicator. We will check the run capacitors with a meter and see what that indicates.
Is it possible for the run capacitors to make that change? I don't have the knowledge to know if they were bad if that would still allow it to run but just at a higher slightly higher amperage. There are 2 run caps so maybe just one is bad and the other is good?

 

[ptonsparky]

Those thermals do give up the ghost but acknowledge that it may have been running overloaded all this time.

Eta: Look at the cooling fan.

 

[ruxton.stanislaw]

That sounds like a tricky situation with the 10HP single phase 230V motor tripping its overload on the dust collector. Here's a breakdown of some possible causes and steps you can take to diagnose the issue:

Possible Causes:

• Overload: Even though the current draw is slightly above the FLA (Full Load Amperage) rating of 39 amps, a continuous draw of 41 amps for 30 minutes could be enough to trip the overload, especially if the motor is operating in a hot or dusty environment.
• Internal Motor Fault: There could be an internal issue within the motor itself, such as worn brushes, faulty windings, or bearing problems, causing excessive friction and heat buildup, leading to the overload trip.
• Dust Collector Clogging: A clogged dust collector filter or blocked duct work can increase the load on the motor, causing it to work harder and draw more current.
• Incorrect Wiring: Double-check the wiring connections to ensure everything is properly connected and there are no loose wires or shorts.

Troubleshooting Steps:

1. Clean the Dust Collector: Start by thoroughly cleaning the dust collector filter and any ducts to minimise the load on the motor.
2. Monitor Current Draw: Use an amp clamp to monitor the current draw over time. If it consistently exceeds the FLA rating, the motor might be overloaded.
3. Check Motor Temperature: Use a non-contact thermometer to measure the motor's operating temperature. If it's excessively hot, it could indicate internal problems.
4. Inspect Wiring: Visually inspect the motor wiring for any damage or loose connections. Ensure proper grounding.
5. Consult Motor Manual: Refer to the motor's manual for specific troubleshooting recommendations and potential solutions.
6. Consider a motor repair expert: If the above steps don't resolve the issue, it's advisable to consult a motor repair expert with experience in motor troubleshooting. They can perform more in-depth testing (e.g. insulation) and diagnose the problem accurately.

Additional Tips:

• Check for Warranty: If the motor is relatively new (3-4 years old), it might still be under warranty. Contact the manufacturer to see if a warranty claim is possible.
• Motor Age and Usage: Consider the motor's age and usage history. Depending on the operating conditions, a 3-4 year old motor might be nearing the end of its lifespan.

By systematically checking these potential causes and taking appropriate troubleshooting steps, you should be able to identify the culprit behind the overload trips and get the dust collector's motor functioning properly again. Remember, if the issue seems complex or requires specialised tools, consulting a motor repair shop can be a good option.

 

[texie]

How 'bout we just start with the basics. What is the actual measured curret as measured VS the namplate amps?
When it comes to centrifical blowers and pumps it is often nothing more than the over load device doing its job because the motor is overloaded due to too much flow. Seen this many times with commercial pools and dust collection systems as well many other similar types of equipment.

 

[Galt]

Run cap.

 

[JB86]

Thanks again for all the tips, so the problem is solved and here is what we found.

I asked the owner if he had done any preventative maintenance and greased the bearings. He hadn't, so he did that and said it immediately sounded different. That seemed to help on amperage but only slightly.
My journeyman went out and tested the run caps, they were both bad, replaced them and now we are running around 28 amps.

So my new question is, does anyone have a good link or resource for better understanding run capacitors.
Before this point, I always just assumed that the motor wouldn't run as well (or long) as it was before tripping out the overloads if the run caps were bad.
As well as what happens if run caps aren't sized appropriately, I assume it won't run at its optimal performance. But will you get the same results if the caps are undersized verses oversized?