Questions about 3 phase motor

[Lee Alkureishi]

Hi all,

I picked up a very nice baldor motor (IDNM3587T) from my local scrapyard yesterday, and have a few questions about it. It's a 3phase, 2hp baldor industrial motor. I've attached a pic of the tag.

1) It looks to be in good condition, and the spindle spins freely and coasts to a stop. I was planning to wire it up to my VFD to check if it runs. Can I damage the VFD if something is goosed in the motor, or is there anything else I need to check before powering up? It's currently wired for 440v, but I'll be rewiring it for 230v.

2) The main arbor shaft is 7/8", but on the back of the motor there is a smaller 5/8" arbor sticking out. What's the purpose of that? It looks too short to be for a buffer/grinder, and that wouldn't make much sense given this motor's intended application..

3) The tag says the motor is 1740rpm/ max 6000rpm. Does that mean that the motor can be run at higher frequency (using a suitable VFD) for those high speeds? What's the downside of doing that, if any?

4) What does the "TE" stand for after the horsepower rating?

Thanks in advance for your advice,

Lee

263654

[Jim Neeley]

Lee,

You can find the official specs and download the owners manual directly from Baldor here: http://www.baldor.com/products/detail.asp?1=1&page=5&catalogonly=1&catalog=IDNM3587T&product=AC+Motors&family=Inverter+%2F+Vector%7Cvw_ACMotors_InverterV ector&winding=05WGW611&rating=40CMB-CONT

It looks like you may gave gotten a great deal; a new one retails for over $1500.

Jim in Alaska

[Erik Manchester]

Lee,

It appears that the motor is designed for inverter duty (i.e. VFD) so that will work well for you. According to the picture at the encl link Jim provided it appears that the stub shaft at the other end may be for a cooling fan of some type to ensure air flow is maintained in some applications. If you are using it as a hobbiest you are unlikely to make that motor really work in most cases so I would not be too concerned. Nice find!

[Stephen Cherry]

the picture on the link has an encoder, which tells the motor where it is positioned.

If you have a doubt you could start the motor using a clothsline around the shaft like a lawn mower pull start. Inverters can overspin a motror above the 60 hz speed, but the drives run out of voltage so the power drops off.

[Gary Radice]

Nice motor, nice find. Way to keep your eyes open. While you have it apart for rewiring, you might also consider replacing the bearings. Even though they seem to spin freely now, you don't know what it will do at speed, and you don't know the motor's history. Bearings are just a few bucks and not hard to replace, and once done you can probably forget about it for 20 years or so. (the counter argument is "if it ain't broke....").

[John McClanahan]

Since the motor is designed to run at slower speeds, the small shaft may be for an extra cooling fan to make up for the reduced cooling when the motor is running at slower speeds.

John

[Lee Alkureishi]

I took the motor to my local motor repair shop today. They tested it and - it runs!

Very pleased... It'll need some new bearings, but once that's done I'll have a $1500 motor for the princely sum of... $12 from the local scrappie :D

Thanks for all the info. I'm leaning toward seeing how hot it gets without the cooling fan - can always add one later. All that cast iron should act like a big 'old heatsink... I also don't think I'll run it faster than rated - not sure my VFD even allows that.

Thanks again,

Lee

[Phillip Gregory]

Baldor's site notes that the motor is a TENV (totally enclosed no ventilation) motor. It does not require a fan and you can safely run it without one. The website notes the motor is equipped for mounting of encoders and position monitoring, which in the applications I have seen would mount to the motor shaft. The 5/8" shaft would either be for the mounting of encoders/position sensors or for the (unused) mounting of a fan if the general design of this TENV motor is also shared with the TEFC version.

BTW, 6000 rpm on that motor would allow you to run up to a 206 Hz input frequency on your VFD unless my math is off. The only downside I can think of would be that you massively overspeed what the motor is connected to, for example a saw blade or a cutterhead. That could lead to destructive disintegration of the blade or cutterhead which would be a very dangerous thing.

[Lee Alkureishi]

Awesome, thanks for the info!