Explosion proof servos

craigsimon · Feb 1, 2005

I am looking at designing a machine up for our own internal use. This machine will be grinding aluminum and be located in a grinding booth. I have done this in the past and had a hard time finding a 7.5hp brake motor rated for Class II Div 1 Group E. The process engineer would like to see a more automated machine where it would automatically do a size adjustment by moving a stroking wheel and belt hieghts with a servo motor. I have looked on the web and I have my distributors looking, but does anyone know of any servo motors that are rated for the above classifications.

I don't believe these will be easy to find, or realitily cheap, if found. But before I tell the process engineer that we will need to re-visit his demands, I would like to exhaust all options.

There is other ways to accomplish what I need, but I would like to look at the explosion proof servo motor first.

Thanks

Hundikoer · Feb 1, 2005

If you coose 3 phase motor (exposion proof ofcourse) and it has "vector control" etc then with encoder and high-end VFD you can get same result. It should be cheaper also.

Havent heard any Ex servo, but sure there are some in the market.

rsdoran · Feb 1, 2005

Reliance Electric: http://www.reliance.com

http://www.reliance.com/Products_motors/xp_brakemotor.html

http://www.reliance.com/pdf/data_sheets/raps_904.pdf

They also offer explosion proof DC motors and drives that may be applicable. I dont think they offer servo but I am sure they can offer a 7.5HP and drive system that will match your application.

Yaskawa/Magnetek also offers a variety of explosion proof motors and drives.
http://www.yaskawa.com/site/products.nsf/products/Industrial AC Drives~ACMotors.html

craigsimon · Feb 1, 2005

I have found braking motors, but I was looking for servos. We need to move a lot of mass fast with very good accuracy.

I have found encoders that match my classification, so one option would be as Hundikoer stated. I would need to look at what tolerances and speed I could get away with to utilze a VFD and and encoder.

rsdoran · Feb 1, 2005

Thats why I mentioned Reliance first, the brakemotors can be used with a VFD but I have also worked with their DC systems for years in explosive/hazardous environments in a variety of applications requiring speed, position and torque. They are worth a close look, maybe a discussion with a rep on your specifications.

Explosion proof encoders are easy:
http://www.beiied.com/main-product.html

Hundikoer · Feb 2, 2005

If you belive that 3phase motor is good enough (it really is) you shold contact with RA distributor (if RA is OK for you). They do the sizeing depending on application. I think they should offer Reliance motors (probably with integrated encoder) and Allen-Bradley PowerFlex 700S VFD.
Wish you luck!

e-osull · Feb 2, 2005

EEx Rated Servo's

Hi Craig,
Just do a search for EEx rated servo motors, there are loads including Allen Bradley 1326AH Range.
Can't be sure of your specific size requirement, they are out there.

Regards, Gene

craigsimon · Feb 2, 2005

Thanks, But

A/B Hazardous Duty Motor 1326AH are not rated for what I need. I need Class II Div 1 Group E. This includes Magnesium and Aluminum dust. It is very hard to find servos that are rated for that. I have found AC motors, DC motors, and encoders, but no servos. I will have to look at doing something like rsdoran and Hundikoer stated.

Thanks for all the help.

Hundikoer · Feb 2, 2005

Please keep us informed.
Extreme applications are usually (hardcore?) fun.

BR
Lauri

BTalbot · Feb 2, 2005

XP servomotors

I don't know if its to late but here's a company thats in Minnesota
I've used their roller screw actuators and servogearmotors and their great.
http://www.exlar.com/products/rotary/ER/er_oview.html

panic mode · Feb 2, 2005

just curous - why it has to be servo? for grinding machine?

kamenges · Feb 2, 2005

I guess I have the same question as panic mode. 'Servo' drive systems don't have a monopoly on torque level or speed regulation. They have a monopoly on torque to inertia ratio and efficiency.

Alot depends on your load to motor inertia ratio. If your reflected load inertia is much higher than your motor inertia (say 10:1 or greater) your motor inertia won't make much difference in the greater scheme of things. If your inertia ratio is more like 2:1 then the motor inertia is a big deal and a PM servo is probably called for.

Just keep in mind that just because you have a large mass you need to move quickly you are not necessarily locked into a PM servo.

Keith

craigsimon · Feb 2, 2005

To BTalbot,
I already looked at that site and the are only rated for Class I.

For Keith and Panic Mode,
It doesn't have to be a servo, I thought I would look at that route first. I don't have all the info on the gearing and inertias, but the final linear speed needs to be 80"/sec with a high rate of acc & decel. Also the accuracy should be +_.030" but I think I could get away with much more slope.

dash · Feb 2, 2005

Have you looked at Elwood Getty Servos.

http://www.elwoodcorp.com/gettys_sx.html

I believe that they are actually the manufacturer of the A-B explosion proof servos. Also you can get motor profiles for some of their more common servos for interfacing with A-B Ultra 6000 & 1394 servo drives. You just have to do some digging within A-B to get to the right person to help you out.

They meet Class 1 Div 1 C & D. Do not know if that by exceeding the requirements of your application that will be OK to use in that application. I am sure that someone at Getty can help with that decision.

There is also one other manufacturer that I am blanking out on right now.

Found the other mfg. It is Kollmorgen which was bought by Dannaher. It is the EB Series servos & the link is

http://www.danahermotion.com/Sectio...000&L3=10901100&L4=&L5=&L6=&IT=Descrip&lang=1

jdbrandt · Feb 2, 2005

Indramat MKE's

Indramat MKE's might work.

Explosion proof servos

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