Elcom Pittman Brushless DC Motors

[Prboz]

Can anybody let me know where I can get some information on these motors? Ipurchased some old HDD Array robotic arms and have approximately 4-6 of these. I have tried to find the pittman site but could not find these motors. They are a purple anodised Square Aluminuium housing.

Would there be a driver board I could use with these?

TIA

Prboz

[RJSheets]

Here is their home page.

http://www.pennmotion.com/

I hope this helps

[Herbertkabi]

hi Folks,
You cant find not any info about these motors from Pittman homepage. I have bought some robotic parts too and got four Elcom-Pittman motors + drive card for all of these four. With this driver I will see a lot of problems - dont believe I can get it work - this is 250mm x 450mm large board with four mosfet power stages and a huge amount of else stuff - unfortunately my brain is not able to understand how to connect it. But these motors are good enough. I have four different sizes. Using some kind of knowledge about motors and because curiosity - I took apart the biggest one of theses - appr 90mm x 50mm x 50mm, shaft diameter 9mm.
It has 30mm diameter 4 pole rare earth magnet rotor, 63mm of lenght. Its coated with yellow brass. Bearings made in Thailand (NMB), typical Slotless configuration, wound with appr. 0.5mm wire (visual). Although the rotor is balanced (see attached picture), it is unfortunately not made very well - I have detected some kind of unbalance - so can forget to use it like (very) high speed spindle motor. But like servo its very good. Now it is in full working order again (included optical encoder) and I have tried it with Schulze future 55Wo speed control (RC stuff) - it runs great up to 5000 rpm when 20V power suply, seemest voltage could be used much higher because very low no load current I detected. Torque hasnt been measured yet, I have no time right now to set it to my test stand but with my own hand can feel that torque is great - at that it need to be - it has 30mm diameter and 60mm long stator.
Before finish my short story I just like to image my wonder that up till now you have not used rc brushless speed controls as well as rc brushless motors like bought from shops as well as selfmade ones like High Speed Spindle. I have built several spindles. The biggest one is >1kw 50.000 rpm max. I do not use 50k rpm , of course, I use somethere like 10.000...30.000 rpm. Voltage I use 14V....20V and current goes at few ampers up to 15A. Very seldom higher. I have built all these motors myself. This bigger one uses some parts from another motors, like well-balanced rotor (for shaft I use stright shank collet schucks - this is the only thing what is near impossible to make myself like bearings are).
Best regards,
Herbert

[Prboz]

Hi Herbert,

Did you get these to work with a controller? Is there a controller that is freely avaible as a kit or open source?

I have about 6-7 of these things from a hard disk array and would like to use them on my CNC router which I am currently building.

Thanks

Prboz

[Herbertkabi]

Im not strong enough in electronics, because I have even not tried this controller board. This board is waiting his time ;-)
I use brushless controllers for radio control for Spindle drive, have built several bldc spindles myself, 10k...20k rpm, even up to 50k RPM.
I like to have closed loop system with servomotors for my cnc but unfortunately my cnowledge is weak about. Up till use steppers.
Regards,
Herbert

[2muchstuff]

Where could I go to find out how to build a 1kw brushless motor for splndle use.

[Herbertkabi]

hi 2muchstuff,
At first: What RPM you need and what size endmills you like to use ?
My bigger spindle makes max 50k RPM and has >1kw max power but in reallity I never need this amount of power because use 1mm ... 6mm end-mills. It waits upon of spindle shaft and collets you use. I use 1/2" straight shank collet chucks (1...7mm collets) or spindle shaft from some existing straight-grinder like Makita. As well as 50k RPM is ... so-so ... 25k rpm is far enough by my opinion. I use four thin section creamic bearings on the lower side and two of theses on the upper side of spindle. These bearings can handle up to 120k rpm. I use light preload against axial slack but anyway - when rpm goes more than 25k a lot of heat will be detected coming from bearings.
Motors I have built myself. Fully-self-built as well as rebuilt from some existing motors. Slotless design as well as slotted. Inner-rotor as well as outer rotor design. I can tell you - some RC motors are very good for spindles. Especially some well-known motors but a little bid older models what you can buy much cheaper from eBay.
Regards,
Herbert