Motor starter opening every afternoon around the same time

[brantmacga]

Around 2PM every afternoon, customer’s dust collector motor starter opens. I would attribute that to how hot it is in this warehouse (around 100 F degrees) and exposing a defective component. I’m not really a motor guy, but would assume its a bad solenoid as i replaced the coil and it didn’t help. The solenoid is boiling hot in the afternoons.

Any tips on other items to check? Could the heat be causing issues with the start switch?

 

[ActionDave]

Is the motor running for the same duration before the starter kicks out?

Has anything changed, been added, or taken off of the dust collector?

How old is the motor? Could be time to change the bearings or change the motor.

 

[jim dungar]

What do you mean by opening up? Is the overload relay opening? Is the starter coil simply dropping out? What devices turn on and turn off the starter? Is the solenoid controller by the starter.
Solenoid and motors are often to hot to touch, you need a thermometer.

 

[ptonsparky]

Which employee wants a break about that time?

Not sure how the solinoid is arranged. Does it control the motor via starter or the other way around?

 

[David Castor]

Do you mean the overload relay is tripping? That could be temperature related. If the contactor is simply dropping out, that would indicate a loss of control power to the contactor coil or a coil failure. Anything that can turn off the dust collector could be the cause. But it can't be the coil if you can restart it.

 

[brantmacga]

Do you mean the overload relay is tripping? That could be temperature related. If the contactor is simply dropping out, that would indicate a loss of control power to the contactor coil or a coil failure. Anything that can turn off the dust collector could be the cause. But it can't be the coil if you can restart it.

Its dropping out. I've already tried a new coil to eliminate that. There is a start & stop button on the face of the enclosure. The motor isn't overloading it. They're telling me it always starts around 2PM, and once it starts, it will continue dropping every 45-60 min for the remainder of the day.

 

[brantmacga]

Is the motor running for the same duration before the starter kicks out?

Has anything changed, been added, or taken off of the dust collector?

How old is the motor? Could be time to change the bearings or change the motor.

Customers states around 2PM every day the contactor drops out, and once it starts, will continue happening every 45-60 min.

Nothing has changed, and motor current is well within spec. I checked the dust collector filters to be sure its not clogging up. Not sure of exact age but I think this one is maybe 10 years old.

 

[hillbilly1]

What is the voltage at the coil? Could be enough voltage drop. That would explain why it is so hot. Check in the morning, then check when it starts to malfunction. If it is a 240 volt coil on 208, excessive voltage drop would be a big factor. Utility or service may be overloaded.

 

[don_resqcapt19]

The overload relay is a thermal device and it sounds like it is getting too hot from the combination of the motor current and the ambient temperate. If that is the case, you could replace the overload device with an ambient compensated one.

 

[LarryFine]

They're telling me it always starts around 2PM, and once it starts, it will continue dropping every 45-60 min for the remainder of the day.

That tells me it's thermal, and ambient heat contributes.

Anyone have a thermal imager/camera handy?

 

[brantmacga]

Thank you for all the responses; I’m reading them all. I will go back to the facility tomorrow and get more details.

The input voltage is 480Y, and there’s a control transformer to provide 120v to the coil. I’ve made two trips to the facility and both times control voltage was normal.

 

[jim dungar]

Thank you for all the responses; I’m reading them all. I will go back to the facility tomorrow and get more details.

The input voltage is 480Y, and there’s a control transformer to provide 120v to the coil. I’ve made two trips to the facility and both times control voltage was normal.

You need to be there to see it happen. I don't think you are being told the full story.
If no one is physically resetting the overload relay and it is not set to automatic reset, something else is causing the starter to be turned off. Once energized, most starter coils will hold in even with as little as 65% of rated voltage.
Chase out the control circuit, maybe there is a thermal sensor in a duct.

 

[zbang]

You need to be there to see it happen. I don't think you are being told the full story.

Definitely, and install a data logger if you can.

("Every day around 2" is too regular to be a coincidence.... unless.... I've seen a few problems where the sun hitting a device caused it to stop. Are there any optical or temperature sensors that get the sun around then?)

 

[ptonsparky]

I've had bimetal overloads that would open just far enough to drop out the coil but didn't require a reset. I know, impossible, but it took a long time to find it and I was standing there. Furnas DP contactor with an overload block.

 

[ptonsparky]

Update?

 

[Krusscher]

Is the overload set to reset automatically? other then that I would think it's something else in the control circuit for that starter coil.

 

[Tulsa Electrician]

Is the overload set to reset automatically? other then that I would think it's something else in the control circuit for that starter coil.

I was thinking same thing.
It may be set to auto
Take it off auto and and some one will call. That of course if you do have one and it's set to A.

 

[brantmacga]

Update?

still having the issue.... I did go back and take some pics on friday, I'll upload and discuss hopefully tomorrow. thanks for asking.

 

[Jraef]

Which employee wants a break about that time?

Lol. I have run into that myself, at Boeing no doubt! An employee was pushing the Test button on an overload relay in a crane starter when he wanted a break. It would take the crane maintenance people 10+ minutes to get there, a half hour to troubleshoot making sure the motor was OK, then they would reset and test that everything was fine until the next day. In total it was usually 45-60 minutes every day. We were there working on new cranes in the catwalks and the crane maintenance guys told us to keep our eyes open around that same time every day. Sure enough we saw him open the cabinet, stick his hand in, the crane would shut down and the alarm light would go off. We even saw that he had arranged some crates to make himself a hidey-hole to nap in, but he didn’t think of the fact we could see him from above!

 

[JimInPB]

If the overload is tripping, I would look to see if the dust collector is getting full & plugged up, which might increase the motor load. If the contactor is dropping out without the overload tripping, then I would hang a few volt meters across different places & look for a change. Does a very large piece of equipment start up right around the time the duster trips out? Is there a voltage drop on the mains when that happens? Checking motor current & looking for an increase might also provide useful information. On some equipment, I permanently install panel meters to aid in troubleshooting.