The Shop => Electronics & IC Programing => Topic started by: dawesy on January 20, 2014, 08:03:54 AM

Title: new VFD help
Post by: dawesy on January 20, 2014, 08:03:54 AM
hope this is the right place for this.
i had purchased a new VFD for my lathe, its a chinese huangyag one, maybe not the best. now at first i had some issues with setting this up (see my other thread 'is my motor toast') :bugeye:
now it was working fine but the other day whilst using the lathe there was a loud bang, a flash from the inverter and all the power in the shop went off. :zap:
after turning off the VFD and restoring power i checked the wiring going to and from the inverter for shorts but everything seemed fine.
gingerly i turned on the VFD there was a very quiet pop and it lost its 'magic smoke' :scratch: there was no display or anything.
i contacted the seller and they have agreed to replace it which is good. :thumbup:
now my questions are:-
i have read that if they have been stored for a while, VFD's need to be 'conditioned' before use to protect the capacitors? is this true and if so whats the best way to do it?
also when setting up i missed that the base frequency was set to 400hz :doh: ( which caused the problems in the other thread) could this have led to the failure (although once setup correctly it did run fine for 45mins of use)?
or was this just a dodgy unit that was going to fail anyway.
just want to make sure that i dont inadvertently do anything to damage the replacement.
thanks in advance for the help guys, you guys  :headbang:
Title: Re: new VFD help
Post by: John Rudd on January 20, 2014, 09:44:24 AM
Sorry to hear of the premature demise of your inverter......
As it happens, I have two of these units. One is currently running my Eagle mill and the other is sat in its box.......
Strange that the initial 'noise' took out all of your begs the question on how the wiring is in your shop...last thing you want is to lose the lights at night.....

To the failure, I suspect the loss of smoke is down to a minor issue with the vfd, can't really comment on the big bang you've found no sign of a short....
Capacitors are known to deform over time but a looooong time, reforming them is by applying a small voltage over a period and gradually increasing it....

Why yours has failed? We'll never know I'd say....

Good luck with the replacement and check your fuses...., :zap:
Title: Re: new VFD help
Post by: dawesy on January 20, 2014, 11:57:14 AM
Thanks for the reply. Wiring is fine. Installed to modern uk standards. The lights did go out but fortunately I had a clear path out, and I could have used the torch on my phone though didn't think about it at the time :doh:
It was like a dead short. With the bright flash. Just wanted to be sure it wasn't something I did that made it fail. Although the vfd has protection measures built in so I'd hope any issues with the spindle would shut down the vfd.
Title: Re: new VFD help
Post by: lordedmond on January 20, 2014, 01:15:09 PM
It can happen with the shall we say lower end units ,most likely the rectifier section flashed over

Please donot be offended but could a stay chip from the lathe have entered the unit ? I have not seen a ip6 one, they should be enclosed and ventilated as required.

I have had good results with Mitsubishi to telmecaneque units but they are a bit pricy

Title: Re: new VFD help
Post by: John Rudd on January 20, 2014, 01:27:27 PM
Irrespective of the make, unless they are IP6x rated! they need additional protection.
My Chinese unit is mounted on the wall above the mill and enclosed in a plastic enclosure....
Even my lathe, which has an IMO vfd, is enclosed......anything to stop the chips getting in and the magic smoke getting out....
Title: Re: new VFD help
Post by: dawesy on January 20, 2014, 01:55:35 PM
I don't think a chip could have got in, I'd mounted the vfd out of harms way but it wasn't in a cabinet. I have built an enclosure that the new one will go in. It will be sealed but have filtered vents to allow for cooling but keep dust out. Let's hope it was just a dud :/