I got a chance to measure the 240v 3 phase motor that I'd like to replace with a compatible 240v single phase motor but I'm not seeing alot of interchangeable motors out there. The issue seems to be shaft size, the original motor has a 3/4" shaft size and a 5x5-1/2" bolt pattern. Looking at the NEMA chart 145T is about as close as I can find but I'd have to bore out the 2 step pulley to for the 145T frames 7/8" shaft. I'll keep reading.
-
Welcome back Guest! Did you know you can mentor other members here at H-M? If not, please check out our Relaunch of Hobby Machinist Mentoring Program!
SB Heavy10 240-3phase lathe - 240-single phase 50amp shop/shed
- Thread starter Bc40ton
- Start date
When I opened up the lower cabinet today all the wires were disconnected, maybe that's why the po sold it and gave me a Chinese vfd, bc he couldn't get it to work properly. So I just thought for now I'd get a 240v single phase motor to get it up and running. Looking at the vfd instructions I got to say I'm a little intimidated :/
- Joined
- Feb 2, 2013
- Messages
- 4,104
The 3/4” shaft creates a little problem, but I was able to do it when I did the retrofit on my first Shenwai SW900B
Have a look here
matching a chinese frame motor with a NEMA frame will not be easy
i did a conversion on a lathe with a 3 hp motor & VFD control, it may be of interest...
www.hobby-machinist.com
and with a 2hp motor/VFD here...
www.hobby-machinist.com
of the 2, i like version 2 better- it was easier and less expensive, but the trade off was patience in finding components cheap.
it turned into a game to see how inexpensively i could do it and still retain my...
i did a conversion on a lathe with a 3 hp motor & VFD control, it may be of interest...
Huanyang VFD Conversion, Shenwai SW900B 1236 Lathe
I did a VFD and 3 phase 3 hp motor upgrade to my Shenwai 900B lathe, because i had a problem with the anemic single phase 1 hp single phase motor the lathe came with. the issue was really evident when parting stainless. so much as to make me want to do the upgrade. i wanted to use the original...
www.hobby-machinist.com
and with a 2hp motor/VFD here...
VFD Retrofit - Shenwai SW900B 1236 Lathe
I finally got around to doing the retrofit on my Shenwai SW900B 1236 lathe it came with a 1.5 hp(ish) 115v/220v single phase motor, as the OEM powerplant. i had to change that :grin: i surfed the site that sounds a lot like E-PAY, and found an inverter rated 2 hp motor by Marathon, very...
www.hobby-machinist.com
of the 2, i like version 2 better- it was easier and less expensive, but the trade off was patience in finding components cheap.
it turned into a game to see how inexpensively i could do it and still retain my...
It’s possible to run your 3 phase motor on single phase, with a drop of available hp , by adding 50Uf per hp capacitance for the missing phase .
Capacitor may cost $25 or thereabouts
There’s also the possibility of using a 56 frame with a 5/8” shaft and using pulley bushing to get the 3/4” bore situation handled, if you were so inclined.
Last edited:
So if I have this in my head correctly, if I wanted to use the vfd the po gave me I do not use any of the wiring in the cabinet. And I run 240v to the inverter and the output from the inverter to the motor, nothing else. All the different parameters are a little intimidating but I suppose the worst I can do is watch the escaping smoke. I'll read some more and look at 56 frame motors and eventually make a decision. Thanks everyone for all the info and advice.
- Joined
- Feb 2, 2013
- Messages
- 4,104
Correct, the vfd output will go directly to the motor.
You can use control wiring to use an apron switch or push button switches or anything else that you want to add- but the inputs will come from the vfd’s DCM circuit and sent through the switching devices for control.
An external potentiometer and/or a remotely connected control panel/display for the vfd can also be useful if you don’t want or don’t have access to the vfd’s control panel display during operation.
You can use control wiring to use an apron switch or push button switches or anything else that you want to add- but the inputs will come from the vfd’s DCM circuit and sent through the switching devices for control.
An external potentiometer and/or a remotely connected control panel/display for the vfd can also be useful if you don’t want or don’t have access to the vfd’s control panel display during operation.
- Joined
- Feb 2, 2013
- Messages
- 4,104
i have retrofitted many motors in my working life, the 56 frame seems to fit just about everywhere obsolete frame motors , at least in my experience .
Often times the drive ends need to be adapted for oddball shaft sizes.
Thank Buddha for SH sheeves and sheeve bushings , they take the place of original v belt sheeves in a great number of the retrofits.
Often times the drive ends need to be adapted for oddball shaft sizes.
Thank Buddha for SH sheeves and sheeve bushings , they take the place of original v belt sheeves in a great number of the retrofits.
- Joined
- Jan 2, 2019
- Messages
- 7,303
Yes,
Since you already have a 3 phase motor installed, and a VFD it's fairly simple to hook it up and see if it will work.
The VFD will have 2 inputs for single phase, that's L1 and L2 from your 240v service. It will have 3 outputs, they will connect directly to the motor, it doesn't matter how to start. I recommend removing the belts for this step.
Post some pictures of the wires coming from the motor so we can get a better idea how to advise.
John
Single steps.
Check the vfd you have, if it has a display and controls, use as is for testing.
Also, assume it is smoked, the person may have smoked it trying to connect it.
Get the manual and read the setup part, 3 times.
Look for and read the instructions for reseting the vfd to default.
Untangle the wires coming out of the motor.
There should be a wiring diagram if dual voltage, hopefully, single voltage so 3 wires.
Connect the 3 motor wires to the output terminals.
Connect a cord to l1 and l2.
Be sure safety ground connected.
Remove or untension the belt.
Plug in and follow instructions for startup and adjustment.
If it does not work, reset vfd to default and start over.
Do the above and report back.
If it works you can add the remote controls.
Sent from my SM-G781V using Tapatalk
Check the vfd you have, if it has a display and controls, use as is for testing.
Also, assume it is smoked, the person may have smoked it trying to connect it.
Get the manual and read the setup part, 3 times.
Look for and read the instructions for reseting the vfd to default.
Untangle the wires coming out of the motor.
There should be a wiring diagram if dual voltage, hopefully, single voltage so 3 wires.
Connect the 3 motor wires to the output terminals.
Connect a cord to l1 and l2.
Be sure safety ground connected.
Remove or untension the belt.
Plug in and follow instructions for startup and adjustment.
If it does not work, reset vfd to default and start over.
Do the above and report back.
If it works you can add the remote controls.
Sent from my SM-G781V using Tapatalk
Well, I disconnected the wires in the cabinet and opened up the plate covering the motor wiring in the back of the motor and there's 9 wires. On the inside of the plate (pic) there's a wiring label. I gently cleaned it up and wired it according to the lower voltage diagram (is that the correct one). Found some 12 awg romex w/ground and attached it how I think the label and manual led me. Plugged it in, lit up and no smoke. Did a reset and tried to enter Ulma Doctors numbers (pic). Some were entered successfully others not so. I felt bold by then and twisted the dial. Dang if she didn't start turning but I have no idea of the rpms so I just stopped for the night. I have to revisit the programming to write down my numbers Fri or Saturday and will post them. So all you guys are awesome, I'll try to get out there tomorrow. 
Last edited:
