Thread: Hello and can I get help, my VFD from new router tripping RCD

3 phase power is not double the single phase
as U phase hits max volts the others are gaining voltage or dropping voltage , never are 2 phases opposite each other to give double the volts , 180 single phase , too 220 2 phase sounds abit low , ( 415/240 = 1.7291 , 220/180 = 1.2222 ) so it is abit low , ( haven't tested mine )

so dose your shed have a 10amp ( 2400 watts ) RCD beaker ??? and how many watts are you pulling , including lights fans , beer fridge ???

move to another power point completely off that circuit to test

last time some one asked it ended up being dust inside the VDF unit ???

as for the earthing spindle motor tripping RCD, UNPLUG EVERY THING VDF first , then unplug the spindle motor , and stick a multi meter (set on ohms setting), on the 3 pins and one leed on the body of the motor , your looking for a ground leak
, your meter might put out a large number so look for the " measurement " indicator , M or mega (million ohm )range is fine , K or (thousand ohm) under 500(guess) is not OK , also you should have the same ohms between all 3 pins , yes there are 4 pins , but only 3 are connected

EDIT , just did some calculations ( ohms law) , a RCD needs 50mA to trip , so at 180 volts ,50mA current needs a resistance to ground ( internal coil wire ,too, outer casing ) of 3600 ohm or less , also make shore there is water in it when you test ,
if you dont get a low reading , using your 3rd hand turn the spindle 360 deg while holding the 2 multi meter wires , might be a coil wire touching the casing only in one position inside the motor , it might not show up if centrifical force is involved , but then the RCD will only trip at high rev , low rev it wont ( hard to test for)

Thanks for the reply Saw,
I'm lucky the house had three phase on, so had it sent to the shed so have three phase if need be. I have a few different circuits to plug the into. I have been trying different arrangments. For the last lot of attempts i have been running it of my 15amp welding point. Still tripping and its the only thing on that RCD.
Have a 40amp three phase MCB with earth leakage at the main board that feeds the shed and another identical rated unit as the first point of all the power to the shed board.

The VFD is new straight out of the box, and i haven't been generating that much dust in the shed recently for it to be an issue but i did blow it out early on it the fault finding mission.
So just to clarify when i multi the active and neutral from the power lead i get 240V
U-V, V-W, U-W 220V
Earth to U,V,W was sitting a steady 180.

Haven't dived into the setting on the VFD yet, wasn't sure if that would then get the seller of side if I did. He has replied to email and is chasing a guy who had experenced a similar issue. That was only today so i'm just putting out feelers at the moment on what it could be.

Will do the OHM test tomorrow, the shed becomes a little cold down here at this time of year and best to have the right layers on!

Thanks for the help,
Boothie

It looks like I may have replied too early to your other post. However, when you measure the 180V between Earth and U,V,W at the VFD, is the spindle motor connected? Try without the motor (DO NOT disconnect the motor with the VFD on!).
If there is any potential between the Earth and U,V,W, you may have a faulty VFD. If iit only happens with the motor connected, my ealier reply is probalby valid - water in the motor.
Joe

Hey Joe,
The values were from the VFD only, no motor attached with the variable pot set to max. F400 on the display. is there any method of testing the spindle for 'leaks' apart from dismantle which is the lest desired action.

Saw,
Thanks just found the EDIT will try the tests you suggest tonight when i get home, got a few croc clips for the multi so not to hard to turn the spindle i hope.

So did the OHM resistance test with the multi on the spindle, earthed to the bolts holding the spindle bracket to Z gantry.
Got a consistant 2.5 OHM on all three pins! Even set the range from auto to only show values 000.0K and so it's not looking good. It did go up to 50 odd Ohm when i turned the spindle. But nothing like what you were saying i should see.
Going to do some hunting on this in the forums now, but i did only start to have this issue when i hooked up the water cooling knowing that i was going to start to get the machine up and running on serious projects.
If you have any further input or info i can use to make my case to have the seller send me a new spindle, please add it as it will help.
Thanks,
Boothie

looks like its a dud seal , thats pretty dangerous 2.5ohm

while the vdf was running that would have been a 72amp short at 180volts , enough to send you across the room if you were the good ground (bare foot wet floor)

lucky for rubber shoes , timber benches , and 1 foot deep sawdust on the floor

"just tell the suppler you have a 2500 ohm short to ground , send me a new one "

edit , wording ??/ >>>>> 2.5 in the range of 000.0K is 2500ohm , enough to trip the RCD (72milliamp )

Saw,
The 2.5 wasn't on the K value to one decimal but on auto range, so it was only 2.5ohm.
Yeah pretty lucky rubber mat under foot to make sure i don't get frozen feet and now with added benefit of not being shocked!
So thanks for the help and will keep you all informed on the outcome.
Boothie

Hello Saw,
Could you just confirm that i have been reading your post right, that the 2.5ohm resistance is not normal for this type of spindle (1.5kW water cooled spindle) I have attached images of the readout of the M-meter. Resistance did go up when i removed the water from the water jacket up to 12.1 Ohms. Still well below what you said I should be getting, the spindle should not have such an easy passage of electricity to ground is that correct?
Thanks again for the support,
Boothie

Hi Boothie, I have the same motor and using a digtal multi meter it reads over 10million ohms or virtually an open circuit between the metal case and the wiring. A special tester called a MeggerOhm meter is usually used to test insulation but if your multi meter is reading that low 2.5 ohm , then there is definatley a short in the motor. Water could be causing the low resistance or you might have burnt out the motor windings and now they are shorting to the case. Did any magic smoke exit the motor at any time? Running the motor below its rated speed or some other parameter set wrong will burn out the coils... as I found out the hard way. Yours ran for only 20 minutes.. is that right?
Drain the water and blow air through to clear any residual water in the jacket. If you unscrew the top of the motor and gently lift it off you will see there should be 2 rubber O ring seals in the water path. I had metal shavings in the pocket for the rings and the metal case around it was wet.
Look to see if it is wet in the top area. Next, mine has a plastic cap with 3 screws over the top bearing, undoing that will let you see the top bearing and if that is wet then water will be in the coils too is my guess. There is a thread about dismantling these motors if you want to try but there won't be much you can do if the coils are burnt. If they are burnt they will look blackened and they will smell really nasty!!!
If it is water causing the short then maybe trying to dry out the motor will increase the ground resistance but it will need time and will need to exceed 1 million ohms as tested with a MeggerOhm meter or very high resistance with a multi meter.
I hope you can recover the motor.. not a good start for you!
cheers
peter

dont take it apart , see if you can get an exchange from the bloke you bought it from first

Hey Guys,
Thanks for all the info, pretty sure its the spindle and not the VFD. Peda thanks for the hard numbers that will help with informing the seller that there is an issue with the spindle and not the VFD. No smoke happened at anytime, the spindle ran for limited durations while setting up and testing with no water in it, just light quick cutting (5 mins) of the testing of steppers and for plotting a big 3,4,5 triangle to test the squarness of the gantry.
Saw, Thanks for helping me get the problem pin-pointed.
Hopefully the seller is going to be as helpful as he has been in the past. Seems pretty good so far, Melbourne based seller so a bit more easily approached than the straight from China option.
Will keep you all posted on the progress, thanks again.
Boothie

Holy crap you lot. What a lot of misinformation and half-truths! If the RCD is tripping you have a life-threatening fault. You get to reset it once. Call an electrician.

So you think if my NEW router which is less than a month old which is not performing in a safe manor is not something to be concerned about. I was sent a spindle, VFD already wired for mains power and instuctions on how to assemble and connect the remaining wire for safe operation. I followed said instruction, including the sticker saying NOT to attempt to adjust any variables in VFD. I then opperate the item for it to trip my earth leakage protection on my worksop. I rechecked my wiring, moved the power supplie to a different RCD and then had similar fault occur. Stopped using the equipment and then looked for information on possiable trouble shooting solutions. I informed the seller of the issue and SPOKE to a qualified sparkie at work who advised me on some other things to help diagnose the fault. Having found values that i had nothing to compare to i looked to a network of people who have similar if not identical equipment who could get me some data to cross reference my data against.

Tool4me if YOU have data or knowledge that would HELP me diagnose safely the problem with my equipment, please feel free to add it to that which has already been offered by the other users of this forum.

Like most here i dare say this is not for business but mainly interest and getting a sparkie out to look at your equipment on the one sunday you get since god knows when to get to the shed, is not going to be cheap.

I haven't used my equipment since i have experenced the fault and trying to get to the bottom of it as best i can, and get as much information to present to the seller for my reasoning that the product he has suppiled is not performing as expected.

Originally Posted by Tools4Me

Holy crap you lot. What a lot of misinformation and half-truths! If the RCD is tripping you have a life-threatening fault. You get to reset it once. Call an electrician..

We all agree - without having to say so - that the condition described is dangerous and needed investigation without taking any further risks. No-one has advocated Boothie to take any chances. An average electrician is unlikely to know ANYTHING about these specialised spindles, will megger it tell you its faulty and to get another one - end of consultation, $80 please (if you are lucky).

WE on the other hand now already know that it is faulty as a result of our conversation, but are curious and actually want to KNOW what the problem is.

So, please assist in this discussion and identify what the misinformation and the half-truths are that you noticed, so that they are corrected and don't get perpetuated.

Joe