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Specifications given for motor suggestions in email to contacts helping decide on a motor:
"The weight we will be spinning will be approximately 2.0 lbs. It consists of an aluminum plate, a 6x6x(1/8)" front surface glass mirror, and a holographic diffuser, all connected to a rod that will be connected to the motor. We have to spin the system consistently at 1200 rpm. Because the drive shaft of the motor will be positioned vertically rather than horizontally, we were advised to use thrust bearings and a lock collar to estimate most of the axial load on the motor. The key feature that is essential to our project is an extremely accurate, consistent rotational velocity. ... Ideally, with our funding and budget, we were hoping to spend about $1200 total on the motor, power supply, and power cable."
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SM34205D -- Smart Motor: A bit overkill for our application, $1,696.70 plus cable and power supply
From Steve:
"One thing to keep in mind is that the power supply’s output will not supply anymore than approx. 8.5A at 115V input. If the motor tries to draw more than that, the voltage will immediately drop to 0V (crowbarring).
The motor can draw up to 9.4A continuous current so if you try and accelerate too fast you will fault the motor. Most of your current draw will be accelerating. Try and minimize crowbarring the supply as it can eventually damage the motor.
QTY ITEM COST DELIVERY
1 SM34205D $ 1,696.70 ea Approx. 2-3 weeks ARO
* Nema 34 class 5 Smartmotor
* 24-48 VDC powered
* (7) on-board TTL I/O
* RS-232 and RS485 ports
1 CBLSM1-3M $ 55.00 ea Stock at Vickers
* Power / serial comm. Cable for Smartmotor
* Main motor connector splits off into DB9 connector and Molex power connector
* Cut off Molex connector and strip wires for use with non-mating power supplies
1 PFC500W-48 $ 240.00 ea Stock at Vickers
* 48VDC 10A output switching power supply (approx. 8.5A out at 115V in)
* 88-264VAC powered
The Animatics is a bit overkill for your application unfortunately due to the other capabilities it has. It can hold a very accurate speed but it’s a bit pricey if that’s all you need."
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34B/FV Series INTEGRAmotor Model 3708 -- Integrated Brushless Motor, Requires Arduino Control
From Steve:
"Bodine-Electric makes an integrated brushless motor that might be an alternative. The control would have to be done on your end. It has an on-board brushless drive but the speed loop would have to be done from your system.
The brushless amplifier requires a 15KHz speed reference in the form of a PWM output (TTL). Your speed depends on the duty cycle. You would then take the encoder feedback from the motor and close the loop on your end.
You would need the motor, cable kit and a 24V (approx. 400W) power supply. That should all be under $ 1200.00
P.S. There is a price on the website for the motor and cable set, you can use that as a reference. The pricing from us will be lower."
From Jason:
"...The downside is that to get an accurate, constant speed you'll need to implement the control system yourself to do it. That would mean some sort of dedicated processor (something like one of the beefier arduinos might do it) that would read the encoder, calculate the motor's rotational velocity, compare it to what you want for a velocity, then adjust the duty cycle of the PWM going to the motor/amplifier to correct for the delta. There's sort of an art in doing all of that - it depends on how fancy you want to get and how much time you want to put towards it."
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SM23165DTD -- Smart Motor: Requires 2:1 Belt System, $901.55 plus cable, power supply, belt system
From Steve:
"The smaller SM23165DT might be a good fit. Using the same 48VDC power supply and cable I quoted earlier, you can get approx. 150 oz-in at 1200rpm using a 2:1 belt system. The power supply has a voltage adjustment POT. You’re going to want to set the supply output to a lower voltage (around 41-42VDC). The motor can tolerate a higher voltage but with your relatively large inertial mismatch, the motor is going to act as a generator when you decelerate. The generated voltage is going to add to the power supply voltage which may push it over what themotor can tolerate.
The SM23165DT is $ 901.55 ea
One other thing I would recommend is using a shunt for back EMF. The shunt kicks in at 49.5V and drops a resistor back across the motor power leads for protection.
The shunt is $ 152.00 ea
Other items:
Cable $ 55.00
Power supply $ 240.00 ea
Total $ 1348.55
If you need to stay closer to $ 1200.00 you can drop the shunt but personally I would use it if you have the choice.
(See 42VDC chart below – continuous torque)"
From Jason:
"Adding in a belt and some pulleys does complicate your setup a little more. Just be careful about what belt you decide to use - you really want a light-weight endless/seamless belt for your application - that will help prevent random "glitches" as the pulley passes across where the two ends of the belt meet. (If you stop by sometime I can show you the one that was used on the scan mirror of MISI.
Putting the shunt on is a very good idea, that will help prevent from roasting your motor or the power supply.... though if you're very careful about how you ramp the speed up and down you can mitigate part of those problems."