trouble shooting when you arent there

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electricalist

electricalist

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dallas tx
I have a customer who has 10 hp motor that is a blower that dries cars at a car was. This is 1 of 10. He said this am the OL trip on the starter tripped first thing this am and keeps tripping . Its a few hrs from where i am, any tips on things I can tell him to check?
The voltage at the starter/ line /load/ loose connections
The voltage at the disconnect /line /load/loose connections
He doesnt have a amp probe.
 
Jraef

Jraef

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If after checking the blower mechanics themselves as suggested and they are OK, check the air ducts, if any. Often the blowers in car washes are just squirrel cage type right at the end of the tunnel with just a little elbow to direct the air onto the cars, so they are designed for not having any ducts or vanes for flow control. But if this one is different and there is duct work or vanes, repeated overloads can be an indicator of the duct work being blown out. In other words if the blowers were selected based on a certain amount of air flow through ducts and guide vanes, but MORE air can flow because something is wrong, the motor will attempt to do it all and overload in the process.
 
electricalist

electricalist

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Location
dallas tx
I did tell him to turn off the mcc. Control to that starter as well the disconnect that's in sight and see if the motors turns. The motors have shrouds that probably fit every motor that direct the air. I have seen trash stuck to the intake side so I did as post no.# 2 said.
Then told him turn disc. Off and see if starter engages when turned to on. If so the problem is after the disconnect.
On a side not am I reading correctly when you say duct work. That brilliant if you mean the motors are elsewhere and they duct the air flow out.
 
kwired

kwired

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NE Nebraska
electricalist said:
I did tell him to turn off the mcc. Control to that starter as well the disconnect that's in sight and see if the motors turns. The motors have shrouds that probably fit every motor that direct the air. I have seen trash stuck to the intake side so I did as post no.# 2 said.
Then told him turn disc. Off and see if starter engages when turned to on. If so the problem is after the disconnect.
On a side not am I reading correctly when you say duct work. That brilliant if you mean the motors are elsewhere and they duct the air flow out.
Click to expand...

What he is saying is centrifugal blowers work harder when there is more free flow because they are moving more CFM of air. Put some restriction in inlet or outlet and they move less CFM and therefore less power is asked for from the motor.

Some have a hard time grasping this as they think restriction adds load to the motor but it is the opposite.

If you have a hole in a duct, or other situation that changes airflow - you may be moving more air then it was designed to move and that is what is overloading the motor. Could be inlet or outlet side of blower. This may not be your problem, but if something is damaged, been changed, removed.... it could be the problem.
 
electricalist

electricalist

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dallas tx
be37a33b34e6ada8204986caf96e0e6d.jpg
 
ActionDave

ActionDave

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Little Bill said:
That looks like the line side instead of load. Line usually is L1-L2-...
Load is T1-T2-...
Also looks like there might have been loose connections.
Click to expand...
That is an IEC contactor and the coil wires are on the bottom like the one next to it even though the Line and T labels are reversed. You can pop the cover off and switch it to match but it's hardly worth the effort. I bet that burnt one has been replaced once already.
 
kwired

kwired

Electron manager
Location
NE Nebraska
electricalist said:
be37a33b34e6ada8204986caf96e0e6d.jpg
Click to expand...
Getting close to DIY, but not quite to DIY yet. That picture tells me you better have another contactor when you do show up as it likely has a problem.

And one observation I have is the cover is either assembled wrong and is misleading or Brown power lead (doesn't really matter if it actually is line or load - it will work either way) appears to be running through the aux contact which is not going to be designed for switching as much load as the power contacts and the #3640 control wire appears to be connected to a power contact instead of to an aux contact.

My money is on the aux contact being used for switching power lead is what the failure is here.

This contact may even be welded closed - but has enough resistance to cause enough change in motor current to be tripping the motor overload.

Deposits on the orange power lead may just be from the adjacent failing brown lead.
 
kwired

kwired

Electron manager
Location
NE Nebraska
ptonsparky said:
IIRC, those contacts are all the same, you just rotate the cover as needed.

I suffer from HUA syndrom frequently so please correct me if wrong.
Click to expand...
I don't think the are the same contact, and usually you don't just rotate the cover but rather you remove the coil and rotate it to get coil terminals on opposite side - contacts and cover over them usually remain assembled when doing this - I have to admit I am not real familiar with the A-B line though.

If all contacts are same they should just call it a 4 pole contactor instead of designating one pole as an aux - JMO. Most power circuit accessories are not designed to fit the aux pole on units I have used.
 
electricalist

electricalist

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Location
dallas tx
The person who took the picture is the maintenance man on the property and was only looking for the source of the problem. now that it seems to be found we can order a new starter and schedule someone to go there.
I did call the company that supplied the starter about it looking up side down and got the same answer as ActionDave. The cover can be taken off and turned over depending on which way the starter needs to be. I think a call to A/B is what I should do.
 
Little Bill

Little Bill

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I've worked with several brands of contactors and never run across one with coil on the bottom.

I think either the picture is upside down or the contactor is installed upside down. If you notice the writing on the coil is also upside down.
 
Tony S

Tony S

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Location
Resting under the Major Oak UK
Fine stranded wire should have a bootlace ferrule (whatever you prefer to call them) to keep the strands together. The conductor will spread and the terminal becomes loose with time. If the contactor operates frequently then the problem is exacerbated.

Now because of the introduction of low lead content solder, UK electricians can no longer solder the strands solid as it makes them brittle and liable to fracture. So much for progress.

The contactors look very much like Telemecanique. The top cover is removable so auxiliary blocks can slot in the coupling arrangement as seen in the picture. There?s every chance the top has been replaced upside down.
The coil connections are in the same position as the next unit.


As for my earlier comment, it doesn?t go to well with our lads when someone asks for suggestions before going to the job. It does make a change to get a photograph beforehand.
 
electricalist

electricalist

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Location
dallas tx
In the future I will keep that in mind. The customer is a few hrs away.
I failed to state I was looking for tips on what the problem is so if and when we went we might if nothing else have parts with us.
Sorry for my poor description and info.
 
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