Magnetic Starter on QT-54?

[tigercreek]

Rather than recreating/rebuilding my current compressor I decided to bite the bullet and buy a new one.
I "settled" on the Quincy QT-54 (230V, Single Phase, 24 amp draw) but have a question about startups.
It seems that these compressors come with a modified pressure switch/overload relay that does not require a magnetic starter to ease the strain on the pressure switch and the motor on statups.
I'm curious about owners experience with this and whether it would be beneficial to go ahead install a magnetic starter on this thing when it shows up?
I know I was going through pressure switches regularly on a used compressor I picked up until I put in a magnetic starter - then no more problems.
I'm not looking to overbuild something that works well out of the box - but I am looking to prevent any potential problems. Thanks.

 

[MacMcMacmac]

I would not trust any pressure switch to handle 24A.

 

[matt_i]

My IR-T30 compressor of similar specs has been running on a pressure switch -only for 23-ish years now. I don't run it super hard these days.

Being a Quincy I feel like they aren't just using the bargain basement pressure switch and actually did some validation of their product via abusive testing.

But that said, what you propose is directionally a good thing and might actually help you down the road. Supposing you find yourself needing to go this route in "X" years then it could require a tear-up of your wiring. If you do it now, it will all be setup and ready to go and will be something you're motivated to do without it being "one more thing added to the pile"

The other nice benefit of this project is you have a very easy pathway to controlling the compressor's ability to run via a toggle switch. Just inhibit/enable the coil voltage with a remote switch and now you have full control of when the compressor is allowed to run.

 

[American Locomotive]

The funny thing is, that pressure switch is only rated by Condor for 3HP for "general purpose" use. It probably won't last long before failing.

Since that compressor just has a pressure switch, it also means the motor has built-in overload protection. So you don't even need a motor-starter, just a contactor/relay.

Looks like something like this should work well:

https://www.ebay.com/itm/Eaton-C25B...902226&hash=item1c5a3a3880:g:bjEAAOxyk99RzLOQ

Just put it in an enclosure and off you go.

 

[The Tool Tyrant]

I would not trust any pressure switch to handle 24A.

I totally concur If your compressor only cycles once a week, you could probably live with it, but if you want it to live and be reliable add the starter.

 

[tigercreek]

Seems like everyone here is confirming my thoughts/fears.
I'll probably just get a WEG unit like I placed on my other 5hp compressor and be done with it.
I guess this is one of the cost cutting features Quincy has come up with that should last until it goes out of warranty.
Thanks for the replies.

 

[whateg01]

I would probably still use at least a general purpose contactor for the real current. However, most Quincy compressors don't start under a load. They wait until oil pressure builds before they start to build pressure, so the initial load might actually be less than a smaller compressor starting under a load.

 

[TuxThePenguin]

I would probably still use at least a general purpose contactor for the real current. However, most Quincy compressors don't start under a load. They wait until oil pressure builds before they start to build pressure, so the initial load might actually be less than a smaller compressor starting under a load.

If my understanding is correct, Quincy got bought by Atlas Copco and the QT-54 seems to be a relatively low-end model from A/C and might not have some of the higher-end Quincy features. Also, that sounds like a feature that might be implemented on a pressure-lube pump, no? QT-54 is splash lubricated.

Disclaimer: I might have no idea what I'm talking about and all the stuff I just said could plausibly be incorrect.

 

[whateg01]

It looks like you're right. This isn't a "classic" Quincy compressor. Sorry if I added confusion.

Dave

 

[seber]

The funny thing is, that pressure switch is only rated by Condor for 3HP for "general purpose" use. It probably won't last long before failing.

Since that compressor just has a pressure switch, it also means the motor has built-in overload protection. So you don't even need a motor-starter, just a contactor/relay.

Looks like something like this should work well:

https://www.ebay.com/itm/Eaton-C25B...902226&hash=item1c5a3a3880:g:bjEAAOxyk99RzLOQ

Just put it in an enclosure and off you go.

Built in overloads work on heat. By the time the case gets hot it has often caused insulation problems or even burned out a winding. Magnetic starters are way safer.

 

[MacMcMacmac]

The QT-54 manual at Northern Tool has clear instructions on how to wire up the single or 3 phase motor starter included with the compressor. They must have begun to install this super wazoo pressure switch only recently.