Contactor engages then trips w/in 3 seconds

[DanaeV]

Hello. I am troubleshooting one of our HP Electro-Magnetic Vibrating Feeders. I have checked all fuses, voltages, terminations, etc., I stand by it and have the operator start the feeder, I watch it start for approximately 3 seconds and then it'll kick out. Due to a previous issue that I located (wire nut wore thru caused an arc in the enclosure on the feeder itself) and the age of the system, my first thought was that the contacts are worn/shot. I happened to have one on hand and swapped it out. Once again had the operator start it and again it ran for 3 seconds and kicked back out. I'm looking to see if there is anyone out here that may be able to point me in a direction of what to check next. In this system, there are the following components: Control Transformer, Starter(Contactor), Diode with Heatsink (SCR), 2 Line Fuses, a Transformer Fuse and a control board that appears and test good. The Feeder is a Jeffrey Dresser (No longer in business, only company I've been able to find that still deals with this mfg. is TerraSource), Model M050. Thank you in advance for any help/ideas you may have!

 

[retirede]

Measure the current draw during those 3 seconds.

 

[DanaeV]

Measure the current draw during those 3 seconds.

I'll go do that now! Thank you!

 

[petersonra]

What is "kicking out"?

Likely that device is seeing too much current and is doing it's job.

 

[tom baker]

Often these issues are blamed on electrical but the overloads are tripping due to a mechanical issue. I have seen irrigation pumps trip due to too many zones turned on, pump issues etc. I found it was best to meet with a mechanic

 

[zbang]

What is "kicking out"?

That's the first question...is it a motor overload, a breaker, some safety interlock, etc. Gotta look at each piece and that may take some time and effort.

As Tom said, look for mechanical problems- a partial jam somewhere, too much product to be moved, some loose thing that's fallen into the works, or something like that. If nothing else, try unloading the machine and run it empty, look to see what's moving and what isn't.

 

[Little Bill]

Check the coil and see if it loses power when it stops.

 

[Jraef]

That's the first question...is it a motor overload, a breaker, some safety interlock, etc. Gotta look at each piece and that may take some time and effort.

As Tom said, look for mechanical problems- a partial jam somewhere, too much product to be moved, some loose thing that's fallen into the works, or something like that. If nothing else, try unloading the machine and run it empty, look to see what's moving and what isn't.

These are relatively simple little electromagnetic vibratory feeders, they don't have a motor or overload relay etc. Think of it as a simple little solenoid plunger that is being turned on and off really fast. The control board is (typically**) rectifying and bucking the voltage, then recreating a low frequency pseudo-AC and firing the SCR into the solenoid, controlling the amplitude (mechanical force) and frequency that it vibrates at. The contactor is just there to turn the power to the board on and off. So most likely, the board is doing or seeing something that it shouldn't and is disconnecting the contactor coil power to shut down before something worse happens.

** Depending on the age. More modern ones use a Switch Mode Power Supply type of arrangement (think VFD-like design that rectifies and reconverts), older ones used a linear power supply arrangement. From the sounds of the parts, this might be an older type.