To avoid these ads, REGISTER NOW!

Quincy QR series compressor: how old is too old?

OP
E

EngineerNate

Well-known member
Joined
Oct 19, 2019
Messages
206
Location
Bristol, TN
MKSJ said:
Size of motor and single vs. 3 phase/VFD choice probably comes down to amount of CFM you need, duration of use, service panel amperage and cost. If you do not need more than say 15 CFM, then the least expensive and easiest option is a single phase 5 or 7.5 Hp motor belted to the appropriate compressor speed. You can pick up a 5 Hp WEG or similar motor for $400-500, a 7.5 Hp for $650. When you go above 7.5 Hp, then 3 phase is probably a better option. I have worked with a few other people who had 3 phase 10 Hp motors on their compressors and if I recall the most cost effective VFD was the Fuji Electric Micro Drive FRN0060C2S-2U (3 pahse input 20 Hp 60A output run in a derated mode) they run around $650. Do not get the HY or cheap generic VFD's, they will mostly likely burn up quickly with compressor loads. The issue you will have with VFD's is the panel service and wiring will be much more amps, NEC code is you need a minimum of 125% of the VFD's rated input. I am not aware of how one factors in derating for single phase, which will draw higher current peaks vs. 3 phase. If you go that route I would either call the distributor or the VFD manufacturer technical and ask them the service requirements. You also need to factor in costs of an enclosure, wiring, disconnect, etc.

If you are running a difficult load you want to keep the VFD carrier frequency lower, and also for older motors. Insulating rating is usually not an issue as most 3 phase motors are dual rated and you are running them off of the lower voltage windings. Can't really see the need for variable speed, so probably stay with a single phase 5/7.5 Hp motor but you also need to factor in a magneter starter control box with a contactor and thermal overload which run around $150 for a WEG 7.5 Hp unit.

I have a Champion HR5-8, the pump can either use 5 or 7.5Hp motor. My motor is a 5 Hp single phase 1750 RPM WEG, which seems to be a bit more common these days. It can flow around 17 CFM @ 90 PSI.
Click to expand...
I got a bit heavy on the derating math last night and figured out that the 15 hp Frenic Mini C2 should run the motor just fine on single phase.

Single phase derate is 1/.6 ir 1.73X, and the motor nameplate amperage is 26.6A, so it's on the lower side for 10HP rated motors. 1.73 x 26.6 is ~46A, or one amp less than the max of the 15ho Frenic Mini C2. Twice motor HP is typically recommended because many times the derate lands between the available sizes, so 2X is always a safe bet. I did some checking around it and it seems for a 15hp unit, the Frenic Mini is pretty stout. Some 15HP 230V units have ratings nearer 40A, which would have pushed me to the 20HP unit for those brands/model lines.

I searched around and that drive was about equal cost with a 5hp replacement motor of decent brand and as far as electrical work, I'm having to run a new subpanel for this regardless so the difference in "last mile" infrastructure is minimal on the cost front.

To further help the VFD handle the load and be nice to my neighbors (and for WAF), I've found an appropriately sized DC reactor to wire in to the VFD (used, close in rating to the $300 one Fuji specs for this drive) and a line reactor sized by the 3% rule to put on the AC input, so I should have a really robust drive.

If I end up needing to make things just a bit more gentle because I went with the 15 hp instead of the 20hp, I can always put a slightly smaller pulley on and the motor will pull what it needs. No harm in treating the 10hp motor as ~8 or 9 HP to take a bit of the edge off. I'm pretty confident this won't be necessary though due to the way the QR-25 series pumps start unloaded.

I'll be sure to start a thread for the install and any restoration work I do, and I'll put a detailed breakdown of what I've learned, how I intend to set it up, and how it works out for me there.

Cheers,
Nate
 
To avoid these ads, REGISTER NOW!
OP
E

EngineerNate

Well-known member
Joined
Oct 19, 2019
Messages
206
Location
Bristol, TN
Forgot to mention, part of the motivation to stick with the 15hp model is the infrastructure on the input side. The 20 HP unit needs an 80 or 100A breaker depending on if a DC reactor is installed. The 15, with a DC reactor, should be okay on a 60A breaker, which is a lot less expensive. I plan to install a 100A sub and while there's nothing technically stopping you from putting a 100A device breaker on a 100A sub, it gives me the heebies.

I'm using input amps from the datasheet at this point. I need to confirm this with the vendor when I call on Monday, but my intuitive take is that input current is limited by the input side electronics and cutting a phase cuts out 1/3 of the diodes etc, but doesn't somehow allow the input current rating to increase. Otherwise you wouldn't have a derate for single phase, the system would just pull more amps to compensate for the lost input.

In other news, the seller sent me a video of it running today. Sounded like an old tractor. I love it. I'm making the pickup tomorrow. Wish me luck!

Cheers,
Nathan
 
M

MKSJ

Active member
Joined
Apr 1, 2018
Messages
34
Location
Tucson, AZ
Not to belabor the discussion as to derating, but per the Fuji Frenic Mini C2-Single Phase Ratings, the rating for the 0047 model in derated mode is 26.0A and 27.0A for the 0060. Adding a DC choke does give you a bit more wiggle room, and Fuji does indicate the input current w/wo DC choke. A compressor is a bit more of a difficult load as it gets to maximum pressure, but as you mentioned you can change the belt ratio if the VFD trips. Interesting Fuji is the only manufacture I have encountered that give some guidance as to single phase fusing for 3 phase input units, and they indicate using the same fuse size for both. I can't really see getting away with a 60A breaker for a 10Hp motor, the issue may be the higher current peaks drawn on single phase vs. three phase, the current is not continuous and produces more THD which is damaging to the capacitors and also can effect the service life of components. As mentioned, a DC choke can decrease the fusing requirements, dampen the current spikes and decrease the THD. Possibly with the 0047 with a DCR a 60A breaker is possible, the 0060 would be 80A. Not an electrician, so best to discuss the application specifics with a technical engineer for these drives for the motor FLA and SF.

You might also look at the Hitachi WJ200-110LF, but typically the Fuji drive will be the least expensive option in this size range. The DC chokes I often pick up on eBay at significant less cost then list.

VFD Tips and Tricks | Wolf Automation

3 Tips and Tricks about VFDs! Including- VFD outdoor enclosure ratings, Sizing a 3 phase VFD to accept single phase 230/460V input line and more!
www.wolfautomation.com www.wolfautomation.com
Tip # 3 Sizing a 3 phase VFD to accept single phase 230/460V input line voltage
The general rule of thumb has been to utilize the motor’s rated FLA and multiply by 1.73 (square root of 3). This was a calculation that worked well when VFD’s were overbuilt in the past. As cost reductions are always on the move with a lot of manufacturers, we’ve seen the industry transition from this method to adding a little more safety factor in calculation. The industry has moved on to using the motor FLA x 2 to provide the added safety factor. Some are even using FLA x 2.15 for the needed output current with the really inexpensive drives. This in the industry is called de-rating a VFD. Always keep in mind the ambient temperature and elevation in the selection process and be sure to follow all manufacturers instruction manuals for reference.

With newer drives the derating has been higher, but the general rule of thumb is 2X for full load. I do quite a few manual mill and lathe VFD control systems, and one can usually get by with a VFD derating of 1.5X because you rarely use full power for an extended time.
 

Attachments

  • Frenic-Mini-C2-Single-Phase-Ratings-FECA-AN-175.pdf
    283.4 KB · Views: 0
OP
E

EngineerNate

Well-known member
Joined
Oct 19, 2019
Messages
206
Location
Bristol, TN
Thanks for all the info!

Unfortunately the compressor was a bust. Rougher condition than the photos made it out, lots more rust on the tank than it originally seemed, and worst of all the bearings on the motor sounded terrible.

On top of all that, the owner of the neighboring business walked over while I was inspecting the unit (seller not present) and told me it had been here when the seller moved in, he'd just been kicked out for failure to pay rent for nearly a year, and he didn't technically own the compressor.

I walked.

I ended up bringing this home from a different seller. It's a 340 instead of a 350, definitely needs a rebuild, and I'll need to source a motor for it (575v fixed voltage motor on it), but the tank is externally in really good shape, the compressor looks to have been cared for much better while it was actually in use, and no weird provenance questions.

It has a bit of a knock in one of the bearings, I can't tell if it's a main or one of the rod journal bearings but I think the latter. I popped one of the inspection covers off and there were no chunks in the oil sump, so my guess is it started getting noisy and the factory it was in took it out of service. The owner bought it to fix up and use at home but realized he was over his head.

Additionally and Unfortunately, someone cut all the copper lines out when it was removed from service, including those integral to the pump. If anyone has good high res pics of their 340 with lines intact that'd be great.

I paid $250 for all of it, which was a number I was willing to gamble with if the tank, pump, or both end up a bust.

I'll be sourcing whatever motor I can get the best deal on for this in the 5-10hp range. I'll likely stick with three phase at this point just because getting good deals on single phase stuff in my area seems like a slim chance, and I think for my use the soft start etc will be real plusses.
 

Attachments

  • Screenshot_20220109-194805.png
    Screenshot_20220109-194805.png
    2.3 MB · Views: 26
  • Screenshot_20220109-194745.png
    Screenshot_20220109-194745.png
    2.9 MB · Views: 36
C

Chilly178

Member
Joined
Apr 16, 2022
Messages
14
Anyone know if you can run a QR 350 pump at 500 rpm with a 5hp motor? Or do you need a 7.5hp at that rpm? Also trying to figure out what size pulley I would need for either 4 or 500 rpm.
 
To avoid these ads, REGISTER NOW!
U

u3b3rg33k

Well-known member
Joined
Dec 18, 2017
Messages
4,118
Chilly178 said:
Anyone know if you can run a QR 350 pump at 500 rpm with a 5hp motor? Or do you need a 7.5hp at that rpm? Also trying to figure out what size pulley I would need for either 4 or 500 rpm.
Click to expand...
horsepower scales linearly with RPM on a piston compressor. quincy should have a published minimum RPM.
 
R

redmondjp

Well-known member
Joined
Nov 25, 2014
Messages
2,318
Location
Redmond, WA
You must log in or register to reply here.
To avoid these ads, REGISTER NOW!
Top Bottom