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bollie7
17th Apr 2019, 10:37 PM
Gday All.
About two years ago I bought a Huanyang VFD/phase changer for my Bridgeport clone mill. I also fitted an almost new 2.2Kw 3 ph motor.
Spent a fair bit of time getting it all set up and until today I haven't had a problem with it. I have a remote mounted speed control pot as well as a remote mounted reversing switch with the centre being another motor "off". I also have two remote mounted start/stop switches.
I have only had the VFD set up to use a frequency range from 50Hz to 100hz.
I haven't used the mill much since I fitted the VFD. In fact until this arvo I haven't used it since late January when it was working fine. When its not in use the machine is unplugged from the wall socket.
So this arvo I went to do a small job and thats when I discovered the VFD is not working properly now.

1) I no longer have speed control at my remote controller
2) The does the direction switch work properly. The motor runs but I think its only running at 50 Hz. The direction switch doesn't switch the motor off when I put it in the centre "Off" position. If I stop the motor using the stop button and then change the direction switch, then restart, the motor runs the other way.
Bugger.
Now I haven't had a chance to have a look at it yet so I cant supply any more info at this point, but I thought I'd put this up in case someone else has knowledge of an issue like this.
I'm really hoping its just some sort of programming glitch and not a component failure
As I haven't touched it from a setting up perspective for over 2 years its going to be a bit like starting out from scratch again.
Any info would be greatly appreciated.
I'm hoping to have some time to have a look at it tomorrow arvo.
peter

jhovel
17th Apr 2019, 11:49 PM
Hi Peter,
certainly sounds like some bad/corroded connections. Undo all the control connections at the VFD, wriggle the wires and tighten the connection screws again. Then try again. If that doesn't change anything, check all other control connections at your switches and potentiometer.
Since the VFD itself works and starts and stops the motor, the single and three phase voltage and connections must be OK.
Good luck tracing the control issue.

BobL
18th Apr 2019, 12:09 AM
I agree with Joe.

I hope it doesn't come to this but if all goes totally pear shaped you can always do a factory reset and rewire the thing again from scratch

bollie7
18th Apr 2019, 03:41 PM
Thanks Joe and Bob.
I'm hoping that it is just a bad connection as we are fairly close to the ocean here and everything rusts pretty quickly. I really hope I dont have to rewire it. aaaaaagggggggg. lol
I'll keep you posted .
peter

bollie7
18th Apr 2019, 06:15 PM
Had a bit of a play with it this arvo. Doesn't help that I cant find a lot of the diagrams that I did when I originally set it up.
Checked the control side connections - all good there.
Anyway if I change the settings to control the speed from the front panel rather than the remote pot, then it works fine. My remote start stop buttons are also ok. So I'm wondering if maybe the potentiometer has carked it. I'll have a look at that over the weekend if I get a chance.
peter

BobL
18th Apr 2019, 07:12 PM
Had a bit of a play with it this arvo. Doesn't help that I cant find a lot of the diagrams that I did when I originally set it up.
Checked the control side connections - all good there.
Anyway if I change the settings to control the speed from the front panel rather than the remote pot, then it works fine. My remote start stop buttons are also ok. So I'm wondering if maybe the potentiometer has carked it. I'll have a look at that over the weekend if I get a chance.
peter

Last year one of my VFD pots started behaving strangely - I think it got dirty from me handling it with dirty hands. The effect was the motor would slowly speed up. A couple of squirts of contact cleaner and then bowing it out with compressed air fixed it.

jhovel
19th Apr 2019, 01:11 AM
ow that you mention that, BobL, I'd forgotten about that. It happened one one of mine too (on the surface grinder). It developed a "dead spot" where the motor would stop about the position of the 3600rpm speed I use most often. I just replaced it and all was fine again.
I wish I knew where you can get the quality pot that is in my valve radio from the mid-40s.... it's still perfectly good. Nowadays, I've had quite a few failures: worn out wipers, scratched through resistive tracks, broken off track ends (very mild vibration environment), etc....

bollie7
19th Apr 2019, 09:35 AM
If it is the pot that has carked it on mine, I'll be happy as that's a cheap fix. But on the other hand, I'll also be a bit ticked off as I've probably only used the mill for less than three hours total since I fitted the VFD. Thats not so good from the "quality" <$3 pot.
peter

BobL
19th Apr 2019, 11:09 AM
I've had trouble free performance using the standard Altronics 1W pots on my VFDs and electronics projects.
At work we would usually buy something in the $20 range from Element14.

bollie7
19th Apr 2019, 06:23 PM
Well this morning I disconnected the pot from the VFD to test it. It tested fine. Reconnected the wires to the VFD (these are ones I also disconnected, checked and reconnected yesterday with no change in the fault) tried it out and its now working fine again. I have no idea what the problem was or what I did that fixed it.
Bugger - dont you hate that?
Anyway, thanks for the suggestions.
I'll just see how it goes I guess.
peter

BobL
19th Apr 2019, 06:31 PM
Yeah I hate that.
I suspect a loose connection or it could be that the the pot just needed a few turns?

bollie7
19th Apr 2019, 06:55 PM
Yeah I hate that.
I suspect a loose connection or it could be that the the pot just needed a few turns?

I really don't know Bob. All the connections appeared to be fine, screws tight etc and I certainly gave the pot a lot of turns before I started undoing connections.
It was probably that little Gremlin that moves stuff on my bench or maybe the one that ties any loose cables and wires into almost impossible to unravel knots. lol.
peter

BaronJ
19th Apr 2019, 09:12 PM
Hi Peter,

Based on your comments, I would guess at micro corrosion between wires and screw terminals, particularly since you mentioned living quite near to the coast.

Here I notice this effect the most on the ends of batteries, where the microscopic film effectively disconnects the battery. Spinning the battery in its holder usually clears the disconnection. Its particularly annoying when you put a battery in the charger and when you come back to take it out find that it is still uncharged.