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Author Topic: My spindle keeps shutting off randomly.  (Read 4855 times)

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Re: My spindle keeps shutting off randomly.
« Reply #10 on: February 09, 2015, 05:27:43 PM »
First, circuit breakers should never be used as a switch unless they are rated for switching. If the breaker is switch duty rated it will be marked "SWR", "SDR" or "SW". This also stated in the Teco manual on page 14. (www.tecowestinghouse.com/Products/Drives/fm50.html)

Second, someone at Factory Automation better read the user manual. According to the Teco FM50 manual single phase power HAS to be connected to L1 (R) & L2 (S), NOT L1 & L3.

The breaker is getting warm and tripping when connected the L1 & L3 because L3 is using a part of the internal power circuit reserved for 3 phase power. The breaker is doing it's job and protecting a miswire power connection. Changing the breaker will NOT fix the problem. Almost all single phase VFD's I've worked with ALL use L1 & L2 and Teco is no different.

Either you have a incoming power problem or a defective VFD. Seeing you changed the VFD once already and still have the exact same problem, then it points to the 213-215VAC power, which is low for a 220-240VAC circuit.
Re: My spindle keeps shutting off randomly.
« Reply #11 on: February 09, 2015, 05:32:12 PM »
Dang it! I thought I was getting somewhere!  Back to square one... should I just buy a buck booster and try that?
Re: My spindle keeps shutting off randomly.
« Reply #12 on: February 09, 2015, 07:50:33 PM »
I need some details... is your cnc in a home or business? What size is the VFD and the motor?

Power companies supply 220v-240v power to residential homes. 213Vac is pretty low unless you are located on the fringes of the utility grid. Low voltage can cause problems with air conditioners, refrigs, etc. You can contact the local utility company and have them check the line.      
Re: My spindle keeps shutting off randomly.
« Reply #13 on: February 09, 2015, 08:10:36 PM »
I rent a space in an industrial building.  I'm only using 2phase... but I believe building is 3phase.

3hp motor, FM150-203C. Ac 1phase 200-240v 50/60hz 27/16a
Re: My spindle keeps shutting off randomly.
« Reply #14 on: February 09, 2015, 08:40:30 PM »
Ok... a totally different set of conditions here. Industrial 3 phase is usually 480V, 3 phase then stepping down via transformers to 277/208V single phase as needed for CB panels etc. Willing to bet you have 208V so the measured 213-215V is ok. Between 1 phase (L1) and neutral you have 120V and the other phase (L2) and neutral 120V, and between both (L1-L2) phases 208V or in your case 213V. It won't be 120+120=240V.... that's a whole other story as to why.

Getting a VFD low voltage fault is really an indicator of a incoming power problem. Especially after changing the drive and having same problem. It's possible on of the phases is dropping out or going low just enough to trip the drive. Have a qualified electrician check the circuit breaker panel specifically for lose connections or burned connections where the breaker attaches to the panel bus bar. Its possible to have a normal voltage reading without a load on a burned or lose 2 phase breaker then the voltage drops under a load. Or move the wires to another breaker.

This is a long shot... It could also be someone in another part of the building is starting a piece of equipment causing the the power to dip long enough cause problems.

Let me know how you make out.

 
« Last Edit: February 09, 2015, 08:46:01 PM by geh7552 »
Re: My spindle keeps shutting off randomly.
« Reply #15 on: February 10, 2015, 07:29:00 PM »
Electrician came out checked the breaker panel.  All good in there.

Next step is to call local service. .. but even he said. .. i really won't get anywhere with them. They all have a range of where is considered in the range.

I'll buy a buck booster if it's worth a shot. I can't use machine and need to try things.

Do you think it's worth a shot to try buck booster?
Re: My spindle keeps shutting off randomly.
« Reply #16 on: February 10, 2015, 09:36:00 PM »
You can try a buck boost transformer. What bothers me is the drive specs for Teco fm50, single phase, 3hp is 200VAC - 240VAC so it should work at 213-215VAC. This is the second drive with the exact same problem. Getting two bad drives is a million to one chance. Everything the drive "LV" fault message is pointing to a line power issue.

L1 & L2 only should be connected to the line power for single phase. Did the electrician take a voltage reading with the drive in run mode?

Ok... this maybe a dumb question but are you sure it's not a 460V drive?

 
Re: My spindle keeps shutting off randomly.
« Reply #17 on: February 10, 2015, 10:46:26 PM »
Not 460.

No electrician did not. 

I'll do that tomorrow.  That's AC voltage at L1 L2? What should it be?
Re: My spindle keeps shutting off randomly.
« Reply #18 on: February 10, 2015, 10:46:54 PM »
And the other drive was not a Teco
Re: My spindle keeps shutting off randomly.
« Reply #19 on: February 11, 2015, 08:45:13 AM »
Measure the voltage at the drive terminals L1 &L2 with the drive off then measure again with the drive running and compare the readings. Should be the same with no voltage drop. If you have a 208V system it should be 208V or a little higher. If it's a 240V system it should be around 240V. In any case it shouldn't be less than 200VAC.

The electrician should have tested the voltage... that's pretty basic troubleshooting. I'm running out of ideas.... it's difficult to problem solve without actually seeing the problem.