Install VFD on quincy air compressor

[Karl_T]

Been working on getting my quincy model 325 5 hp compressor running. Installed an Automation Direct GS23 - 2010 to run the 5 hp 1800 rpm 3 phase motor. Kept the motor contactor and wired from this to the VFD single phase 220 and then 3 phase to the motor.

The electrical and plumbing work is a piece of cake for me. NOT SO with VFD programming. I only do this less than once per year and each one seems to work slightly different.

OK changed these parameters from default:

set
group # value description
00 22 1 coast to stop
00 23 1 disable reverse
01 10 60.0 frequency upper limit
01 12 2.0 AC time
01 13 2.0 DC time
02 35 1 auto run on power up


This runs but only by pressing the run and stop buttons. Is there a parameter to tell the VFD to run when it sees power? I was able to do this with a different VFD vendor on my other compressor

OR, plan B, wire command input 1 to the spare contact on the pressure switch and change parameter 02 00 to a 1


After getting this far, the plan is to install an electric solenoid to the unloaders and energize this from start until up to speed. Have yet to research how to wire and program this.

 

[mksj]

VFD will not auto-start if there is not control input telling it to do so. You would need to set 00 21 to 1 = External Terminals. If you had a jumper wire from DCM to input 1 the VFD would start. I do not recommend having the VFD power turned on/off via the contactor with the pressure switch, VFDs need to completely discharge their capacitors before re-energizing, and frequent on/off power cycling will lead to quicker component failure. . Contactor should turn on power to the VFD, which would stay on. One side of the pressure switch would be wired to the low voltage run input of the VFD, use the DCM to input 1. You could use the other side of the pressure switch to activate a timer relay to activate a solenoid for the unloader, just use something like 5 seconds. There is also a programmable relay output on the VFD that could be used for the unloader, but these have limited voltage and current ratings so I use them to trigger a solid state relay. I am assuming the unloader relay/solenoid would be 230VAC single phase so would want to use a dual pole relay.

You would use program B interval power on, and have the timer set to 5 seconds. A1 and A2 is 230VAC, trigger is A1 through the other side of the pressure switch. Be aware that there are different versions of these multifunction timer relays some only operate off of 230VAC, others takse a wide range of AC an DC voltages. This is the easiest approach, but I can also look into the VFD programming for the relay output as another option.

Amazon.com

 

[Karl_T]

OK, got tricky with the start/stop. Three way to starter contactor. Normal operation will kill VFD power when pressure made. This keeps SWMBO happy as VFDs puts out interference that gets her favorite AM radio stations. 362 days a year the air compressor will only run less than 1 hour a day.

For painting sandblasting etc. flip this switch to always on and a second switch goes through the second pressure pressure switch contact to D11/Fwd. Now the VFD stays on full time.

 

[Karl_T]

Wish I had asked earlier about the unloader issue. I like mksj suggestion in post 2 but I had already bought and installed a 24 volt air solenoid.

looked up the way my 10Hp quincy was done five years ago. See pic. This has worked great.

OK, this wiring means the VFD has to supply 200 milliamp of 24 volt for 2 second at startup. I looked and looked and looked for a rating on the VFD 24 volt supply, no joy. So, am aksing for trouble? Just try it? Or is there a cheap 24 volt supply I should buy?

 

[Pevehouse]

Been working on getting my quincy model 325 5 hp compressor running. Installed an Automation Direct GS23 - 2010 to run the 5 hp 1800 rpm 3 phase motor. Kept the motor contactor and wired from this to the VFD single phase 220 and then 3 phase to the motor.

The electrical and plumbing work is a piece of cake for me. NOT SO with VFD programming. I only do this less than once per year and each one seems to work slightly different.

OK changed these parameters from default:

set
group # value description
00 22 1 coast to stop
00 23 1 disable reverse
01 10 60.0 frequency upper limit
01 12 2.0 AC time
01 13 2.0 DC time
02 35 1 auto run on power up


This runs but only by pressing the run and stop buttons. Is there a parameter to tell the VFD to run when it sees power? I was able to do this with a different VFD vendor on my other compressor

OR, plan B, wire command input 1 to the spare contact on the pressure switch and change parameter 02 00 to a 1


After getting this far, the plan is to install an electric solenoid to the unloaders and energize this from start until up to speed. Have yet to research how to wire and program this.


View attachment 514017

View attachment 514018

Glad you’re posting this. Looking at an identical Quincy 325 for my shop. Would have to run it off of a VFD as well. Guy is asking $1500 for the compressor though. Hoping he will come down a little,lol

 

[mksj]

Karl, you are most likely asking for problems if trying to use the VFD internal supply, they are typically rated for 30-100 mA@24VDC, you also have the issue of a reverse voltage spike when the solenoid releases and that can cook the power supply w/o a snubber diode. There is also the instantaneous on current when the solenoid turns on. There are inexpensive small universal power supplies that will run off a wide range of voltages 100-240VAC, I would just add that and use the VFD relay trigger. I assume the relay trigger is programmed to go off after a fixed time. Noise and interference on the radio is typically dealt with an input filter and sometimes a shielded motor cable, I have not had this issue. I do not know which VFD you are using but some are more problematic then others. I still would be concerned with potential of rapid power cycling of the VFD, I have seen a few occurrences where the inrush circuit died.

This is what I use for when I need minimal power in a thin supply, they have other versions. but 0.63A should be fine.
DIN Rail Power Supply Meanwell HDR-15-24 24V 15.2W 0.63A UL TUV

 

[Karl_T]

OK, stupid to take a chance for only $18. Ordered one from amazon

 

[Karl_T]

I ran the unit a few cycles without the unloader. It draws 22 amps coming up to speed and then 15.+ amps running. The motor FLA is 14.4. Is this a problem? Of course the VFD don't care as its 10Hp rated. I should be able to drop the starting amps when the 24 volt supply for the unloader arrives.

Extra bonus question. This GS-20 VFD needs the MENU button pressed four times to display amps. is there a way to have it always display amps? The current default display is frequency, not much use on a unit that always runs at 60.

 

[sdelivery]

Don't forget the factory unloader valve keeps the compressor unloaded when there is low/no oil pressure, like at start up.

 

[Karl_T]

The previous owner had disconnected it. I found out why, it has a small air leak. Pretty common problem, the heads in the unloader have a three inch diameter rubber diaphragm. This will be no big deal with the air solenoid as the unloader will only see pressure for 2 seconds at startup.

I learned the hard way on my previous VFD install. Unloaders are meant to work for 1/2 a second when motors come immediately up to speed. Not the slow ramp of a VFD. The air solenoid bypasses the mechanical unloader air valve and allows an easier start.