Electro-Craft 0703-02-018 data

[brassdrift]

Does anyone have data on this motor, or know how to go about getting it?

I need to match a servo drive to it, so would like to know voltage and current ratings. Any more info beyond that would be a bonus.

Electro-craft Part# 0703-02-018. (Permanent magnet DC servo motor and tachometer.)

[mike_Kilroy]

i think 0703 gives basic motor data:

google search of partial no gives:

In Stock Servo Motors for Sale | A1 Servo Motor Repair

[Al_The_Man]

My listings show 644 then 721 nothing in between, Electro-Craft/Reliance made many OEM to order motors and in the past this has been the source of more than a few odd numbers showing up.
Al.

[Bob La Londe]

Look in the Hurco forum. There are some 0703 motors used on Hurcos. The ones on my Hurco mill say 45VDC on the spec sheet, but the power supply actually provides 84 VDC to the servo drivers. Its only going to see that peak voltage under the heaviest possible load though. Ploughing through material at feeds way faster than you can cut well at. Mine is an 0703-02-0409 I think. I'ld have to walk out to the shop to see, and I don't feel like putting my shoes back on.

For a step direction input DuGong, Viper 200, and Gecko might be ok, but the Gecko says it maxes at 80VDC.

[brassdrift]

Thanks for the quick responses. Looks like some consensus on 45 VDC. Surprisingly low, but will save a bundle on servo amps, at least for initial setup, glad I didn't buy anything over-spec. Might want to replace these later, but just happy to get running easily for now. That's enough info to get going, thanks a bunch!

FYI, it's a Shizouka AN-S mill, stock build from SK Systems. All electronics were stripped when received except the original motors. Peeled at least .030" of crud off everything to find ways with almost no wear, and ballscrews indicating zero backlash as well as I can measure. I think it sat as a retrofit project for 10-15 years with someone who never finished it.

The motors seem undersized for this machine. Wonder if there's a good reason.

Spindle motor is 3kW. Maybe this size feed is fine for that. As mentioned, you shouldn't need to run the feed too hard if your chip load is anything sane. Unless you have load from something else -- but this might be the best condition of machine I've worked with to date, and I don't expect the machine to derate at all compared to any of the ridiculousness I've dealt with before.

Don't know of any simple relation from spindle power to feed power. Would be useful to consider if such exists. Of course I'll find out in practice pretty quickly if overloads occur in normal use.

[Al_The_Man]

You can confirm the supply voltage by backfeeding the motor at a known rpm and measure the generated DC, if you assume a maximum of 3000rpm which was around typical for these motors, extrapolate the value to the 3000rpm.
Also most modern drives to not use a tach, just remove the brushes for use with Torque mode drives.
Al.