Another modern brushless DD motor to experiment with!

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dmills
Posts: 190
Joined: Sun Jun 16, 2019 3:33 pm
Location: Uk

Another modern brushless DD motor to experiment with!

Post: # 59088Unread post dmills
Fri Aug 06, 2021 12:31 pm

So Some of you may remember my more or less accidentally acquiring a NSK brushless DD servo motor about a year back to experiment with.

Turns out the driver really did not consider speed to be a first class citizen and was all about positioning, which is fine as far as it goes, but not really what we want for our use.

I considered designing a replacement drive card that took speed seriously, but the thing also had significant cogging tendencies which were going to be hard to get rid of completely in an after market motor control card, so I have put that one aside for the time being.

What I really wanted was a DD BLDC which was coreless (Hence no tendency to cog), well, turns out such a thing DOES exist... Enter the Yaskawa SGMCS-05 and friends (Be a little careful some of the bigger ones do have cores), 5Nm (Steady state, about 15Nm for a second until the coils over heat), and available on ebay for a couple of hundred dollars brand spanking new (As opposed to well over a kilobuck list).

Course I had to have one to experiment with, and today it turned up.... Only trouble is it doesn't come with the connectors for the motor cables, and EVERYONE is out of stock :x !
IMG_20210806_170726.jpg
The Yaskawa driver has a speed mode, but it is analog input, so will need an external pll to lock it to target speed annoying enough that I may just design my own drive card eventually, but it should work alright for now.

Just wondering if anyone has played with this sort of thing in a platter drive application? 50kg/cm (Using the weird units that seem to go with turntables) is very attractive, and the price is not too bad.

Chipmageddon is really getting on my nerves at this point, nobody has any stock of anything, goddam vaccine manufacturers buying up all the microchips! :mrgreen:
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leemichael
Posts: 55
Joined: Mon Jul 13, 2020 1:43 pm

Re: Another modern brushless DD motor to experiment with!

Post: # 59290Unread post leemichael
Mon Aug 30, 2021 5:30 pm

Looks solid, you made any progress with this?

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dmills
Posts: 190
Joined: Sun Jun 16, 2019 3:33 pm
Location: Uk

Re: Another modern brushless DD motor to experiment with!

Post: # 59304Unread post dmills
Tue Aug 31, 2021 7:42 am

Biggest hold up at the moment is that nobody has the plug for the feedback connector actually in stock!
Literally there is zero stock out there, and without it I cannot wire the servo pack to the motor.

I have tried running it open loop at a few hundred mA three phase sine from a stack of power amps and a computer sound card and the thing does run, but without the feedback you cannot really do FOC and get the stability I am after.

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evildrome
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Joined: Wed Jun 21, 2017 6:55 am

Re: Another modern brushless DD motor to experiment with!

Post: # 59469Unread post evildrome
Thu Sep 16, 2021 10:20 am

Is the plug "special" ?

I've had a lot of experience finding (and sadly making) weird plugs.

Can you post a picture of it?

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dmills
Posts: 190
Joined: Sun Jun 16, 2019 3:33 pm
Location: Uk

Re: Another modern brushless DD motor to experiment with!

Post: # 59473Unread post dmills
Fri Sep 17, 2021 5:30 am

Its just a JAE circular industrial thing, Mouser should have stock end of the month, so I am just waiting on it coming in.

Dont know what it is with servo motor manufacturers, they just seem to pick the weirdest connectors for both the motor and the servo amplifier ends of the cables (The servo amp uses a firewire plug for the feedback).

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