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Author Topic: Poor repairs  (Read 501 times)
lloydsp
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« on: June 11, 2019, 14:20:52 pm »

We had a Delta 10HP VFD fail a while back.  We bought an identical model for replacement, then sent the bad one to a 'repair outfit'.  We received it back about 20 days ago, and I did some relatively-trivial testing to see it work.  It seemed to.

The repaired unit seemed as if it was working fine.  Unfortunately, the only jobs we've had for it over the last 20 days have been fairly-trivial 1/8" drilling patterns in soft PVC foam.  Today at 6am, I switched to 0.995" Forstners, and the spindle stalled on every hole!

So, I lost an hour trouble-shooting, then swapping the unit out for a known good one.  And the machine is back to normal.

I won't name them, yet, because they swear they'll make it good.  If the company makes it good, I'll let you know who and where they are (USA).  If they fail or refuse, lacking a full refund, I'll let you know, too! <grin>

Lloyd
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lloydsp
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« Reply #1 on: June 12, 2019, 01:22:02 am »

OK!  The company is Galco, Inc.  They will not pay for return-shipping for an item they 'repaired', but which does not work.  They won't even offer to refund my shipping costs if the unit comes to them defective!

I'm still sending it back, because we need a working spare.  But, DON'T do business with them!

If they fail to fix it this time, I'll litigate (or at least threaten-to) to get a full refund on ALL costs, including the original shipping costs.

Lloyd
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dh42
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« Reply #2 on: June 12, 2019, 01:45:24 am »

Hello

Nice !!  Roll Eyes we have the same here  Cry

A Chinese one
https://www.ebay.fr/itm/10HP-220V-7-5KW-34A-Variable-Frequency-Drive-VFD-Huanyang-Inverter-CNC/264209198710?hash=item3d84186e76:g:cagAAOSwIt5ccARm

and if it don't works, they will said .. "no problem, we will send you a brand new one" ! (this has happened on a guy that "make smoke" with is CNC spindle at the first try)

 Grin Grin Grin Grin

but never send your spindle to repair   Shocked Shocked Shocked Shocked

https://www.youtube.com/watch?v=i-Uwum25VSw

++
David
« Last Edit: June 12, 2019, 02:01:14 am by dh42 » Logged
lloydsp
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« Reply #3 on: June 12, 2019, 15:59:41 pm »

David,
Do you operate yours on single-phase or 3-phase power?

I ask, because I haven't find any really clear guidance on how much to de-rate such an inverter when used on 1PH power.  So, we de-rate by 60% (just to be safe).

If you operate on single-phase, how much do YOU de-rate your units?

Thanks,
Lloyd
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dh42
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« Reply #4 on: June 12, 2019, 19:25:39 pm »

Hello

I've 2 VFD, but they're not HuanYang model.

The first one is a TELEMECANIQUE, 380V tri to 380V tri (drill press), the second is a FUJI, mono 220V to tri 220V (CNc spindle). Both are the same power as the motor. In the past I also have a big DANFOS 5Kw 380tri to 380Tri VFD but used with a 550W motor  Shocked ... The 550 W motor run without problem on the 5Kw VFD (this was an old one VFD without settings)

I know that on most VFD, like the HY, you can set the max current for the motor in the settings (I do that on an 1.5Kw HY VFD used on a 800W motor) ... It's what you want to say with "de-rate" ?

edit: mono = single phase

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David
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lloydsp
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« Reply #5 on: June 12, 2019, 20:21:04 pm »

David,
The best I can tell, one needs to de-rate the output of a VFD by about 58% when operated from a single phase (usually L1/L2).  So, if it were rated at 10KW on 3-phase, it would produce only 4.2KW on a single phase.

I feel 'safe' de-rating mine by 66.6%, so I'm "inside the margin".  I have a 5 HP spindle running on a 10 HP VFD, but on single phase.  Since I never use (or have used) more than about 60% of the rated output of the spindle, I feel )(marginally) safe there.

Lloyd
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dh42
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« Reply #6 on: June 12, 2019, 20:38:30 pm »

Ah Ok !

In my case I don't have the choice to use 2 or 3 phases as input as on a HY, the TELEMECANIQUE 3 phase VFD works only with 3 phases as input and the FUJI can only use 2 phase as input ...

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David
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Bob La Londe
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« Reply #7 on: June 12, 2019, 20:45:00 pm »

I seem to recall reading 37% in the manual for my Mitsubishi inverter on the Hurco.  Its a 3.7 Kw unit.  I seem to also recall having seen derating figures of anywhere from 33 to 40% in various places.  Never saw any that I recall before about derating by 2/3s.  

I've got Delta, Hitachi, Mitsubishi, Huan Yang, and unknown name inverters in the shop.  I don't recall the name for sure of the one in the Tormach mill, but Danfoss rings a bell.  I know the Danfoss was the inverter on the Charter Oak turd key mill.  

Speedstar Polyspede VFDs are available designed for single in primarily up to quite large capacities.  I looked at using one in 5HP rating on the Hurco at one time, but I have never needed all that power so its been put on the back burner.  

The Mitsubishi has some impressive characteristics and capabilities.  I turned it on at 1000 rpm yesterday to edge find a part with the spindle brake engage.  I didn't realize it until after I shut off the spindle and smelled hot brake pads.  LOL. 
« Last Edit: June 12, 2019, 20:50:05 pm by Bob La Londe » Logged

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