Needs Pictures: 0
Picture(s) thanks: 0
Results 1 to 15 of 51
Thread: Two GMFs and one VFD
-
22nd June 2015, 09:06 PM #1.
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 27,803
Two GMFs and one VFD
Over the weekend I got a really good deal I could not refuse on another GMF 1HP 3P grinder and am now looking at putting my small multitool Linisher onto that grinder as well as making it variable speed.
One thing I did not want to do was fork out for yet another VFD
but
its proposed next door neighbor will be this identical grinder
So I thought, why not use the same VFD with a suitable cross over 3P switch between the two grinders.
Now because of the some individuals who occasionally use my workshop I won't feel comfortable unless there is some sort of lock that prevents switching the cross over while the VFD is running a grinder.
I have in the past proposed using a manual cross over switch placed inside a box, the inside of which is only accessible when the output of the VFD is off.
I was thinking of using a simple 12V door door latching solenoid to lock the door, and the lock is activated by a DPDT switch with the other side activating the VFD.
VFD ON - door locked
Maybe there is some sort of 3P switch that does this already but I expect that it will be pretty ex..
Any other suggestions welcomed.
-
22nd June 2015 09:06 PM # ADSGoogle Adsense Advertisement
- Join Date
- Always
- Location
- Advertising world
- Posts
- Many
-
22nd June 2015, 09:52 PM #2Senior Member
- Join Date
- Nov 2007
- Location
- Rockhampton
- Posts
- 106
-
22nd June 2015, 09:53 PM #3GOLD MEMBER
- Join Date
- Jul 2010
- Location
- Melbourne
- Posts
- 7,775
Hi Bob,
Do you coasting stop or braking?
Stuart
-
22nd June 2015, 09:59 PM #4.
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 27,803
-
22nd June 2015, 10:04 PM #5GOLD MEMBER
- Join Date
- Jul 2010
- Location
- Melbourne
- Posts
- 7,775
-
22nd June 2015, 10:17 PM #6.
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 27,803
-
22nd June 2015, 10:42 PM #7GOLD MEMBER
- Join Date
- Jul 2010
- Location
- Melbourne
- Posts
- 7,775
-
22nd June 2015, 10:53 PM #8.
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 27,803
With the HYs on my DP and WW lathe I used light weight small switches and with the reverse on the same switch
Because the switches are light weight I sometimes flipped the switch to off and through into reverse!
Doing this the VFD/motor goes though its normal deceleration stage and then starts the reverse acc stage.
Then I realise, hey its going in reverse so I go to turn it off and I end up pushing it into few again - no problem.
Eventually I realised I had to be a bit more careful when switching these machines.
That's why I have now gone for more positive acting switches but I'm now used to the lightweight switches and although it still happens occasionally it doesn't appear to have harmed them
Then you wont need my ummmm rather complicated setup then
Stuart
-
22nd June 2015, 11:49 PM #9GOLD MEMBER
- Join Date
- Jul 2010
- Location
- Melbourne
- Posts
- 7,775
Yes, but doesn't sound like you're using coasting stop.
Knock yourself out
There isn't as much detail in the thread as I thought.
To be honest I've forgotten exactly how its wired. The switch uses a 4th pole to switch control of the VSD from one machine to the other.
I think there is something thing in the wiring to stop the machines controls latching on(or maybe they wont turn on at all) unless the controls are plugged into the vsd enclosure.
https://www.woodworkforums.com/showth...ight=enclosure
-
23rd June 2015, 01:52 AM #10.
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 27,803
Ah - you mean am I toggling back and forth on a machine with a coasting stop.
I haven't tried that - the machines with a coasting stop are 2 grinders and the BS.
I will try it out and report back.
Knock yourself out
There isn't as much detail in the thread as I thought.
To be honest I've forgotten exactly how its wired. The switch uses a 4th pole to switch control of the VSD from one machine to the other.
I think there is something thing in the wiring to stop the machines controls latching on(or maybe they wont turn on at all) unless the controls are plugged into the vsd enclosure.
https://www.woodworkforums.com/showth...ight=enclosure
-
23rd June 2015, 02:26 AM #11
If you want a positive interlock, you can get 3phase motor contactors that have mechanical interlocks, when one is energized the other is locked out.
Then you can wire the on/off switch at each grinder to pull in the appropriate contactor, no other changes required.
-
23rd June 2015, 11:45 AM #12.
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 27,803
-
23rd June 2015, 11:05 PM #13GOLD MEMBER
- Join Date
- Jul 2006
- Location
- Adelaide
- Posts
- 2,680
-
23rd June 2015, 11:40 PM #14.
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 27,803
-
24th June 2015, 03:13 PM #15Senior Member
- Join Date
- Sep 2007
- Location
- Country West Oz
- Age
- 77
- Posts
- 201
Hi Bob,
If you connect the VFD output to the line side of a contactor on each grinder (connected in parallel) and then electrically interlock the contactors so only one can operate at a time, you are all sorted, no need for a changeover switch.
When grinder one is running, grinder two cannot be started and vice visa.
If you don't have contactors with the required spare contacts, you could probably add relays to achieve the desired result.
When I do things like that I tend to use whatever I've got about the place, so sometimes it can end up a bit unnecessarily complicated.Regards
Bradford