Magnetic contactor

[forhire]

Tuesday, after a loss of power, the Daikin hydraulic unit on my cnc lathe took a spike when the service was restored. Luckily none of the other electronics on the lathe appeared to be damaged. Early Wednesday I called service and was informed the parts are not stocked and it would take 12 to 14 weeks for the replacement boards to arrive. This machine is my livelihood.... I felt very fortunate to find a replacement power unit in Texas and had it shipped overnight (don't ask the price). I was back up and running Friday morning.

Today I was lamenting my misfortune to my Dad and he suggested I installed a magnetic contactor similar to what I use on all my motors. Well duh!

My question is I can get a contactor that will break if over voltage, under voltage, loss of phase, and maybe even off cycle (hertz). Loss of phase would likely be the most important... but I can wish. Maybe a I need a huge UPS.

I've attached a few photos. The last one is the new unit after being installed.

[irish fixit]

They are out there. The one's I've used have a inductive pickup you just run the wires to the motor through the loops and put the overload into the control circuit. I've not actually been able to find the ones that I've used in a while but here's something similar.

http://www.grainger.com/Grainger/EAT...HL4?Pid=search

[forhire]

Originally Posted by irish fixit

They are out there. The one's I've used have a inductive pickup you just run the wires to the motor through the loops and put the overload into the control circuit. I've not actually been able to find the ones that I've used in a while but here's something similar.

I poked around grainger last night. Over load and loss of phase appear pretty straight forward. I called Platt this morning and I have them working on something. I suspect I'll have to part with a pile of cash.

[Farmerboy]

I ended up buying lost phase and some other items such as hertz monitoring off of Ebay and they all worked fine and were low cost,

[irish fixit]

I didn't have time to do much studying of what was available. I do know that the add on over loads I've used in the past will drop out if there's much of a phase imbalance. I figured there had to be some out there with even more functions.

[MikeGyver]

The damage looks fixable.

[leightrepairs]

http://www.grainger.com/Grainger/ICM...YL2?Pid=search
I think this will do what you are looking for.

[forhire]

Originally Posted by leightrepairs

http://www.grainger.com/Grainger/ICM...YL2?Pid=search
I think this will do what you are looking for.

Good find. Monitors Low Voltage, High Voltage, Phase Loss, Power interruptions, Phase Reversal and Unblanced Voltage... all on one relay! Too bad it's only has 10 amp contacts... but I bet that it can run a contactor. no problem.

The delay time is less the 100ms... which appears plenty fast... I wonder if it's too fast or sensitive that the relay would be tripping all the time. For the price I could buy one and put it on a counter to keep track of the faults per week before putting it in production.

[forhire]

Originally Posted by MikeGyver

The damage looks fixable.

You might be right. The unit still powers for a brief second before it overloads. The display actually shows the preset 3.5 bar.

Once I pull the boards I'll see if they can be sent off for repair. I got a response from Daikin re-stating it will take 12 to 14 weeks... but still no price. I really can't lose anything having them repaired. duaneb55 has a line on someone who has the skills.

If I have time today I'll pull the boards and post some pictures. I need to re-tool the lathe for a small stainless run first.

Update: I just got the quote for the main board... $2345.00. Really? I bought the complete unit for $3500 from Mori-Seiki. I guess they'd rather not fix it.

[forhire]

I pulled the boards this afternoon. Damage doesn't look too bad. Traces are still on the board... might get by with some new caps. It appears that one leg of the three phase must have gone high because the caps on that leg are completely gone. It appears the caps isolated the damage. I might get lucky... I could use some good luck.

[Bluewelders]

So did it blow up some caps,or just a varistor or two ?

[forhire]

Originally Posted by Bluewelders

So did it blow up some caps,or just a varistor or two ?

Both... my bad calling them all capacitors.

Top photo: Z101 appears to be a 430NR-20D (wish my eyes were better) which would be a Metal Oxide Varistor.

Bottom photo C507, C508, C509 are ceramic capacitors. C509 was blown off the board, likely when C508 blew up. C507 "looks" good. All are KH103M X1Y2 capacitors.

[Bluewelders]

A lot of varistors that I have seen fail,failed shorted.
I don't know what would have blown the capacitors,though a motor going resonant will make a plasma blast like that.
Hopefully it didn't carbonize the pc board.

[forhire]

Originally Posted by Bluewelders

A lot of varistors that I have seen fail,failed shorted.
I don't know what would have blown the capacitors,though a motor going resonant will make a plasma blast like that.
Hopefully it didn't carbonize the pc board.

That was my fear also, that the traces would be melted, but the board looks ok. My Allen-Bradly control on another machine had an over voltage alarm when I came in so I suspect unbalanced phase or some kind of surge. I think that control trips the alarm over 265V.

I checked the varistor z101... it's not a dead short but it may short when power is applied. The unit powers for a second and then trips the breaker. If the varistor shorts I'm sure the capacitors before it get over energized.

[Silicon-based]

Even if the traces are not blown, the plastic that the board is made from may be carbonized (what Bluewelders was referring to) meaning the possibility of conductive carbon on the surface of the board. This may cause the board to catch fire (!) or at least to make electricity go where you don't want it to go.

If you try to repair the board, remove the blown components, then brush it with a soft (brass) wire brush to remove carbon, and clean it with isopropanol. The caps and varistors can be got from digikey.com, and are cheap.

John

[forhire]

So Duane's friend finished the boards a few weeks ago. The repair was very affordable. Tonight I installed everything. I think I have it all hooked up right.

Now I need to figure out a way to test the pump. I don't want to install it in the lathe. I'm running heavy right now and I can't afford the down time. I know I can't run it dry. I'm thinking I should be able to run a hydraulic hose from the pump to sump and just let it run in a loop. Can anyone tell from the pictures that I'd be ok looping it? I'm thinking a hose from the top of the pump to T1 on the tank. I just need to power up the pump unit long enough to see that it runs. It's a spare part.

[forhire]

This afternoon I scrounged up a hydraulic hose and plumbed it into the unit so I could test it. Filled it with oil. Wired it up on a 20 amp circuit exactly like the breaker in the lathe. And crossed my fingers.

When I flipped on the power I hoped it would come to life. My biggest fear was the hydraulics spraying everywhere (I tied the hose in). Instead... BANG! and the the shop does dark. It tripped the darn main. So much for the 20 amp catching it. Smoke was rolling out as I remove the side cover. Similar loss as before. Now I'm thinking the motor must be bad causing it to overload. I'm starting to see why Daikin didn't want to repair it... darn slippery slope. Oh well.

[duaneb55]

Well that sure stinks! Literally I'm sure. Now I feel bad.

As we discussed on the phone, the board guy was concerned he couldn't do a more thorough check out not having any info from Daikin on the system. He'll be disappointed it didn't work out.

I presume you're done with it at this point?

[forhire]

Originally Posted by duaneb55

Well that sure stinks! Literally I'm sure. Now I feel bad.

As we discussed on the phone, the board guy was concerned he couldn't do a more thorough check out not having any info from Daikin on the system. He'll be disappointed it didn't work out.

I presume you're done with it at this point?

It was a gamble and this was the spare. In any case I'll keep it around because it has a good pump on it. I guess I really should have checked the motor windings. I just figured the boards got overloaded. I'll check the windings if I can figure it out. It has six wires... so I'm thinking it's some type of servo. At least if I can diagnose that it's the motor it will make use all feel better.