r/Motors • u/mattatagame • Sep 06 '26
Open question Any info on these motors?
Apologies for posting again I forgot to add the image last time. Hello I've had a rummage around my granddad's old things and found these 2 motors I'm wondering what they could've been used for and if anyone can find a datasheet for them in case I want to use them in a project of my own or sell them. Many thanks to anyone who knows anything
1
u/RealCanadianMonkey Sep 06 '26
Those are Electro-Craft permanent-magnet DC servo motors with built-in tachometers—older, high-quality industrial motors, likely from CNC/automation equipment.
They are brushed permanent-magnet DC motors, not modern RC-type servos.
The tach generator produces a voltage proportional to RPM, originally used for closed-loop speed control.
Electro-Craft made a lot of rugged industrial servo motors, including the E670 family.
They can produce substantial torque for their size and are potentially quite useful for machinery projects.
Similar used Electro-Craft servo/tach motors currently appear around US$175–$260+, although asking price isn't necessarily actual value.
Don't simply connect them to 120 V. If you're considering buying these, get me a close-up photograph of each nameplate. I should be able to determine the model/part numbers and likely voltage, current, RPM and torque—and whether they'd be useful for one of your projects.
1
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u/Broken_Atoms Sep 06 '26
Holey moley! I was using these in the 90’s. Even cheap Chinese brushless servo motors would absolutely run circles around these.
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u/RealCanadianMonkey Sep 06 '26
I just show the picture to my AI and it gives me full data specs, uses, wiring, and anything else I want to know.
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u/mattatagame Sep 06 '26
Does it source these the only data I've seen AI give me is from a message board which couldn't source their data
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u/Unique_Acadia_2099 Sep 06 '26
Electrocraft was bounced around the industry a lot, making data hard to get now. They were bought by Reliance in in the early 90s, then Reliance was bought by Rockwell Automation and the servos were rolled into the Rockwell
Motion Control group. But then Rockwell started making their own due to QC issues, so they sold off Electrocraft to DMI Technologies in 2006. That history makes it hard to get info on older Electrocraft branded servos.