TM 1 P / VF 1

[fourperf]

maybe hijacked but all very interesting. Thanks fellas.

happy holidays to all

Mark

[gar]

071230-1553 EST USA

Are your breakers Homelite or QO. Since you mentioned HOM I suspect these are the Homlite and my feeling is that these are inferior to QO.

At our shop we have a fairly stiff power source, about 200 KVA worth of transformers supplying a number of different main breaker boxes. The main box supplying the the CNC machines is 200 A 3 phase at 240 leg to leg, and all QO breakers. Our wire runs are about 50 to 100 ft. I will have to check, but I believe the breakers to the machines are 50 or 60 A 3 phase and these never trip under normal conditions. However, when the northeast US blackout occurred several years ago some may have tripped and we lost fuses in some of the HAAS machines. We have VF2s and VF3s and an SL20.

Also I failed to mention that there are counterfit QO breakers in some distribution channels.

See http://www.mikeholt.com/newsletters....y&letterID=487

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[Edster]

I've got a TL-1 that runs off a 40A single phase circut. It never trips the breaker. Not even when the spindle was stalled trying to cut a big acme thread. It probably helps that the voltage at the shop is 250v though

The haas literature says the machine runs on 208-230v 3 phase or 240v single phase. Since our voltage is 250 I wired the machine up for single phase. Maybe your lower voltage has something to do with your breaker problem and you should be running off 3 phase with a phase converter.

The $3600 phase converter might have been a phase perfect.

[Donkey Hotey]

My voltage is a solid 245V.

I was incorrect. I had a 50A in the main panel, feeding a 50A in the subpanel (I never run the knee mill and TL-1 at the same time).

I upped the main and the sub to 60A today. It fired right up on the first try and I thought I had it beaten. Then I shut it down for three hours and it popped the breaker on restart. It's gettin' better though.

And I made the T-nut for my new/used Dorian CXA toolpost. No more KDK for me

[gar]

I looked at our breakers and wiring today. This is all 3 phase.

The breakers for each machine are located in a branch box on the wall near the machines. One box with two breakers, one breaker per machine, feeds two machines and the other box has 5 breakers and feeds 3 cnc machines plus some other things. From these boxes the 1 way wire length is between 30 and 50 feet. The wire is #8. The breakers are all 40 A for the VF-3s and SL-20, and the newer VF-2. The 1993 VF-2 has a 30 A breaker.

For the so called 20 HP units the peak initial inrush current to charge the capacitors should not be much different for single vs three phase. This is determined by source voltage and impedance. The duration might be somewhat longer for single phase, but may have more to do with total internal impedance of the source than anything else.

In a sense your problem seems unlikely. Is there any possibility you are using a GFI breaker?

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[Donkey Hotey]

Nope, they're standard breakers. I'm not terribly worried about it right now. The Cutler Hammer CH series breakers aren't as common as their BH series. I've been checking the local Home Depot and Lowes. They occasionally get them. When they do, I'll pick up a new 60A and give that a go.