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Crunch
21-09-2019, 06:15 PM
Hi
I have a 3.0 kW Chinese HY Vfd

The image is the same as my vfd,
Terminal 9 states it is the earth connection, if you look at the bottom left and right there are 2 more screws with the earth symbol next to them,

If I test between the 2 bottom earths I have continuity, if I test between either of the bottom earths to the metal back of the vfd I have continuity,

But on terminal 9 I have nothing between the 2 bottom earth screws or the metal back of the vfd, I would of thought they would all be connected,

Can some one tell me if they are all like that or have I got a faulty one.
Many thanks Paul

Neale
21-09-2019, 09:43 PM
Reading the HY manual (well, closer to deciphering the Chinglish) it looks as if you should connect "E" terminal to the usual earth point. Can't remember what I did with mine! Have a feeling that I ignored it, but I've shut up the workshop for the night. Shall try to remember to look in the morning, if no-one else has answered.

cropwell
22-09-2019, 01:15 AM
I've got the 2.2KW and it looks as though those two screws next to the earth designations are just case screws. I get no continuity between any of the three 'earth' screws and no sight of a metal plate. Also the manual does not mention them - it just says grounding is to terminal E.

Kitwn
22-09-2019, 03:33 AM
I remember being puzzled by those moulded-in symbols. Just ignore them and tie all earths to the 'E' terminal.
If you're using heavy conductors and/or have several earths to connect you may want to take a short wire out from 'E' to a separate earth post rather than put too much strain on the small and flimsy connector on the circuit board.

Kit

Crunch
22-09-2019, 08:13 AM
Hi
Thank you every one for your replies.
I'm still confused ,
If I connect all my earths to terminal 9 as manual states, my vfd has a large aluminium heat sink on the rear of it which will be bolted to my control cabinet, as my cabinet is earthed it will earth the vfd heat sink, the 2 bottom screws with the earth symbol will now be tha same earth as the whole system, as terminal 9 is not connected to any of this, won't there be a problem as I have 2 different earth points, based on star ground.
I can't see why terminal 9 wouldn't be connected to the Aluminium heat sink.
Or am I over thinking this.

Can someone just confirm they have no continuity between terminal 9 and there aluminium heat sink
On the rear of the vfd.

Many thanks Paul

Sasquatch
11-10-2019, 10:16 PM
Didn't open mine yet but VFD itself needs earth only for input filters and input and output varistors. I'm guessing that HY doesn't even have either.
Linking all earth on one central bar is common practice in panel building.
Run terminal 9 wire and motor earth to the same point as your cabinet earth.

Crunch
12-10-2019, 08:55 AM
Didn't open mine yet but VFD itself needs earth only for input filters and input and output varistors. I'm guessing that HY doesn't even have either.
Linking all earth on one central bar is common practice in panel building.
Run terminal 9 wire and motor earth to the same point as your cabinet earth.

Thanks for reply, I did do as you and others had mentioned and it was fine.
Thanks Paul