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View Full Version : DC motor conversion on Nova 3000 to EVS



Zeeber
28th January 2016, 05:43 PM
Ok, so I've got the 2.75hp Greenmaster treadmill motor (free) because the electronics were stuffed (speed controls and converters that change it from AC to DC - not sure what they are called). This motor is 220VDC, and has a foot mount.
I'd like to put this on my Nova 3000 to get electronic variable speed, and I thought this motor would be nice because it currently has a 1.5hp CMG AC motor (that cannot be speed controlled because it is a 2 capacitor motor, if I understand correctly).
From what I have read, I should get the KBIC 240 DC unit which will do everything I need to convert AC to DC, then allow me to control the speed.
If anyone knows better, please let me know.
My question is regards the mounting though - the current motor has the D80 B14 mount, in other words an 80mm flange mount. I understand that one can get a flange for the Greenmaster motor that will be a B5 mount (ie same dimensions as the B14, but the flange is bigger then the motor in diameter, not vice versa like the B14). Terribly confusing, and I hope I got it right.
Now, where would one find such an end plate, because I have come up with nothing in all my searching locally. Anyone got an old DC motor that is not working, with such a flange mount maybe? I went to an electrical repairer (Barca J) and the guy told me that something like this does not exist, made me feel like a complete idiot (until he suggested getting a "cheap Taiwanese lathe" if I wanted EVS - clearly doesn't know anything about woodturning. So I found this (if only to make myself feel better):
369896369897

Any ideas of where to begin looking locally?

BobL
28th January 2016, 06:07 PM
I'd say your chances of finding one a very slim and you might have to get it made.

It would help if you changed your "Australia" location to something more specific so that "locally" might actually be more meaningful

Woodturnerjosh
28th January 2016, 08:37 PM
I just did a quick google search on "green master motors" and it appears they only made treadmill motors and it also appears they are no longer made.
So, as BobL said you might have to get one made unless you can find one from another manufacturer that is a direct fit (unlikely) or maybe contact the company that did treadmill repairs and see if they have spare parts.
The motors I did look up have a useable rpm range much higher than the 4 pole AC motor that your pulley ratios are designed for so it would be worth checking the speeds of your motor before going further. (4000 - 5600rpm for a green master DC vs around 1440rpm for a 4 pole AC)

Zeeber
29th January 2016, 07:43 AM
Location Melbourne.
thanks for the feedback, the point of the motor is to be able to adjust the speed, so motor speed range not that critical. I'm sure the motor is generic, doesn't have to be a greenmaster end plate, but no luck so far. Might look at drilling and tapping the existing end plate...

Woodturnerjosh
29th January 2016, 06:15 PM
If you operate a dc motor outside of it's range (as in significantly slower) you will have very little, if any torque and probably burn it out. Yes, the speed will be variable but within the range the motor is designed to operate within.
I'm an armature winder by trade and ran this info by one of the older tradesman I work with to double check.

Zeeber
11th February 2016, 10:25 AM
UPDATE: Thanks for all the good advice, and due to the possible torque issues, I decided to go 3phase and VFD - it's a tried and tested (if slightly more expensive) way, but in terms of the amount of use I aim to get out of it, and the number of years, it should b worth my while.