Cheap DC motor controllers

[BobL]

Does anyone have any experience with these 180V DC motor controllers

Low High Adjustable Input AC 220V Output DC 180V Motor Speed Controller | eBay (http://www.ebay.com.au/itm/Low-High-Adjustable-Input-AC-220V-Output-DC-180V-Motor-Speed-Controller-/150956931030?pt=AU_B_I_Electrical_Test_Equipment&hash=item2325bbf7d6&_uhb=1#ht_1963wt_1156)

I picked up a Treadmill yesterday from kerbside pickup. The unit was so well used that the belt support board was broken into two pieces and most of the labels on the plastic controls buttons had worn away so I had no idea how to turn it on. Anyway I took it apart for the nice rollers and a few other bits and pieces. I figure $26 to see if the motor works is worth it as there will be other opportunities to pick these up.

I assume the worm? drive motor that changes the height/angle is a stepper of some kind?

[malb]

You would be welcome to try the 'suck and see' approach with the speed controller but it does not indicate any output current capability. Most mention I have seen of people reclaiming treadmill motors suggests motors in the range 0.5 - 2HP, so a considerable current (2-10A) would be required. Suggest you look for labels on the motor for voltage and current or power requirements.

With regard to worm geared motor being a stepper, I believe that this is unlikely for two reasons. Worm drives are very lossy due to the end thrusts imparted by the worm feed which has to be absorbed by bearings in the system. In turn steppers are reasonably low power devices, so the combination would have little usable power. Secondly steppers are intended to hold position unless being sequenced to a new position, while it is impossible to reverse drive a worm reduction system (crank the output shaft to rotate the input) to they are inherently self holding as well, so it would make little sense to combine two self holding systems in a single drive.

Elevators for hospital beds, lifting aids etc are generally low voltage DC permag motors operating a pinion and rack with brake system for holding if required and inbuilt limit switches to contain travel. Typically 12 or 24V so they system can incorporate batteries to allow a failsafe mode in case of power failure. Appropriate units are more than capable of lifting an obese human plus the movable part of the bed and matress, bedding etc. I suspect the platform elevator drive would more likely be based around something like this, photo would help.

[BobL]

Thanks Malb, I'll get some photos organise.
The unit says 6A so it's a 1.5 HP motor

[BobL]

This is the info on the DC motor
http://www.woodworkforums.com/attachment.php?attachmentid=260984&stc=1

And on the angle lift motor
http://www.woodworkforums.com/attachment.php?attachmentid=260985&stc=1
As well as the red/black power and green earth it also has a multi core thing running to it.
That looks like a 32:1 ratio gearbox

Here is a pic of the whole angle/lift motor, gearbox and screw mechanism.
The screw is inside the black tube.
http://www.woodworkforums.com/attachment.php?attachmentid=260986&stc=1

[RayG]

Hi Bob,

Have a read of the thread http://www.woodworkforums.com/f65/mars-lathe-dc-motor-conversion-159263/index16.html lots of information on treadmill motors and controls


Ewan used this controller.. KBIC240DS

KB Eelectronics KBIC-240DS DC Motor Speed Control with A57168 Signal Isolater | eBay (http://www.ebay.com.au/itm/KB-Eelectronics-KBIC-240DS-DC-Motor-Speed-Control-with-A57168-Signal-Isolater-/140864304176?pt=LH_DefaultDomain_0&hash=item20cc2ab430#ht_1194wt_1165)

Regards
Ray

Edit changed link to 240DS version for 6A rating

[BobL]

Hi Bob,
Have a read of the thread http://www.woodworkforums.com/f65/mars-lathe-dc-motor-conversion-159263/index16.html lots of information on treadmill motors and controls
Ewan used this controller.. KBIC240DS
KB Eelectronics KBIC-240DS DC Motor Speed Control with A57168 Signal Isolater | eBay (http://www.ebay.com.au/itm/KB-Eelectronics-KBIC-240DS-DC-Motor-Speed-Control-with-A57168-Signal-Isolater-/140864304176?pt=LH_DefaultDomain_0&hash=item20cc2ab430#ht_1194wt_1165)
Regards
Ray
Edit changed link to 240DS version for 6A rating

Thanks Ray.
At $55 for the controller and $67 for the delivery, I might take my chances my $26 with the cheap chinese one.
I have sent them a question asking about max OP current.

[malb]

Looking at the elevator drive and data plate I would suggest that its a bog standard 4 pole synchronous motor (nom 1500RPM) with a 32:1 reduction drive incorporated. Speeds would be slightly lower than stated, abt 47RPM instead of 50 as stated.

Power supply would probably be via the red and black cables, with the multicore supplying forward/reverse by remotely switching the start winding orientation.

Alternatively, could be a universal motor, with reversing controlled by reversing armature connection at connections to the brushholders via remote switching and multicore. Not likely though as the speed would be independant of the input frequency (data plate says 50RPM at 50Hz, 60RPM at 60Hz), and there is no obvious sign of brusholders anywhare in the pic.

Definitely not a stepper if it runs of mains frequency power, unless the multicore takes the power to a power supply feeding a stepper driver and returns power to the motor phases, again speed would not be dependant on input frequency.

Note also that the data plate specs a low duty cycle of 1 minute ON for 8 minutes OFF. Might seriously limit it's potential uses in a workshop.

[BobL]

The cheap chinese controller turn s out to only output 250 mA so that's not a goer.

I think I'll park this motor until I have a more specific need to do something with it.

Thanks to all who commented.