1/5-1/2 hp perm magnet motor

[Muleman]

We are using 24VDC solar power to pump 50/50 glycol-water at remote well locations. We could increase the source voltage to 48V but I'm trying to stay away from anything higher and do not want to go to AC inverters. The calc hp requirements vary from 1/5 to 1/2 hp. They run in a fairly harsh environment, mostly in the winter (-38 deg F last week). We're testing a 24V Bodine motor/controller driving an Oberdorfer gear pump currently, but apparently will have to go to another supplier for anything above 1/4 hp. I'm looking to capitalize on others' experience or a suggestion where I might find the larger motors, preferably 48V to lower line losses. I tried a keyword search to no avail, so thanks in advance for any suggestions.

 

[Clyde38]

Try:
AO Smith
Baldor
Leeson
MicroMo
Moog
to name a few. Also

http://www.globalspec.com/

Good luck....

 

[itsmoked]

What is the magic about 48V?

Wouldn't an inverter let you use way cheaper and more efficient motors and to do other things like speed control and use cheaper wire?

Can you say more about what you're doing?

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[Muleman]

The magic of low DC voltage is that we don't have to be electricians to work on it. We are testing an inverter/AC motor, and since the days I was building them, they are very good and seem to be efficient, but for the cost of the inverter, I can buy a pump and motor.

The DC motor we're testing does have speed control that can be monitored and adjusted via a DCS system without any other equipment.

The glycol-water is heated by a production unit, then used as heat trace to keep lines thawed out.

 

[macmckim]

Another company to try is Pacific Scientific - they mfg a good range of low voltage PMDC motors. See product page.

http://www.pacsci.com/products/pmdc/index.html

 

[blacksea]

Maxon and Faulhaber DC motors' manufacturers would be added to Clyde38' List.
But I don't think that DC motor+velocity amp+AC/48VDC converter would be cheaper vs AC motor+Inverter.

 

[Muleman]

I should have been more descriptive. Preference is for a brushless motor. We can easily hook the panels/batteries to deliver 12/24/48 etc. so we wouldn't need a converter.

 

[cswilson]

If you want to use a brushless motor, you will need some kind of electronic inverter to convert your DC supply from the panels and batteries to the AC the brushless motor phases require. (Remember that a "DC brushless" motor is an AC motor -- it requires AC input to spin in one direction.) A key challenge you will have, I think, is finding one for your environmental conditions. It sounds like even -40C minimum operating temperature will not be low enough. Most devices I am familiar with in this power range are for pretty benign indoor conditions.

 

[itsmoked]

http://web6.automationdirect.com/static/specs/gs1drives.pdf

$99 bucks.. Of course you need 120VAC in, so you would still need to use an inverter. But they are dirt cheap these days.
Perhaps if they are packaged in a safe manner the electrician aspect could be minimized.

While I could build exactly what you're after - If I were faced with the same task, I would try to "off-the-self" the package as then you can learn about the application further.

It would still seem to me that using a small OTS 3ph motor would really save a lot of $$. I could be wrong as perhaps small BLDCM might cost less, though I somehow doubt it.

If the equipment really has to run at -40C you will need to design what you want from the ground up. ouch!

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[DickDV]

Just a thought here. Some of the newest cars are coming out with 48VDC electrical systems. Anything automotive has to be good for very cold conditions, maybe even -40C.

That might be a source for your motor.

 

[Muleman]

OK, Uncle. Based on the cost estimates I have, the material savings are in the range of $100-$200 and we'll eat more than that up in electrician charges, but you've convinced me that we should at least try it. I really like the idea of 3 phase motors, and if the AC driver is somewhat enclosed, it might stay warm enough.

We've got two science projects going now, one more won't hurt--especially when considering we'll eventually be doing this to 450 locations.

You've been very helpful, thanks a lot.

 

[itsmoked]

Science projects. Great term!

Please keep us informed of your results.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[cswilson]

Keep in mind that an inverter designed for AC-line input can typically accept DC input, making the front-end rectifier a pass-thru. We have people do that to our servo drives all the time. In your case, if you want to feed 48VDC into a drive designed for 120+VAC, just make sure that this won't have the drive in an undervoltage-fault condition, and that the logic power can be generated properly.

If you want to use a brushless servo motor, you will need feedback -- probably hall commutation sensors -- and a drive that can use this. An induction motor would not need any feedback.

I have seen several applications for cold ambient conditions where the enclosure for the drive contains a heating element (sometimes a motor shunt resistor is used for this purpose) that warms up the enclosure to start -- then the drive's own heat can keep things warm enough after that.

Curt Wilson
Delta Tau Data Systems

 

[itsmoked]

cswilson; So you've actually seen this huh? I always wondered but got stymied on the fact that the controller - the thing that actually controlled everything - was one of the problem children to start with.

Was that thing you saw a manual thing?
Turn on box power. Wait 2 hours... ?

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com