Osama Sr 1740G Electrical Diagram

Hello

I have been working on the repair of this Osama lathe since June 2021, ugh My father passed away in August
with Parkinson's , then my Uncle passed away the next week, now my mother has a heart condition and not doing well.
I finally got all the contactors I needed and a selector switch and checked out the circuit at a shop with 3 phase 240 VAC and got it to work
using the new contactors and all the limit switches and selector switches. So I took it out to the customers location and installed
the control circuit and it worked great. Spindle forward and reverse . YEA !!! Thank you Hobby Machinist ! ! ! for the electrical
schematic and info on the lathe.

Eric Kesinger
Glad it helped. That was the intent of this sub-forum. These are very nice machines. I see them come up on the machinery broker sites pretty regularly. I think they are a solid option for the hobby / home shop folks who want a lot of capability for reasonable money.
 
Hello

I have been working on the repair of this Osama lathe since June 2021, ugh My father passed away in August
with Parkinson's , then my Uncle passed away the next week, now my mother has a heart condition and not doing well.
I finally got all the contactors I needed and a selector switch and checked out the circuit at a shop with 3 phase 240 VAC and got it to work
using the new contactors and all the limit switches and selector switches. So I took it out to the customers location and installed
the control circuit and it worked great. Spindle forward and reverse . YEA !!! Thank you Hobby Machinist ! ! ! for the electrical
schematic and info on the lathe.

Eric Kesinger
Hey Eric - can you list the contactors you used (brand/model) and which stock contactors you replaced them with? That would be a big help for anyone else who needs to service their machines.
 
Last edited:
Hello

I have been working on the repair of this Osama lathe since June 2021, ugh My father passed away in August
with Parkinson's , then my Uncle passed away the next week, now my mother has a heart condition and not doing well.
I finally got all the contactors I needed and a selector switch and checked out the circuit at a shop with 3 phase 240 VAC and got it to work
using the new contactors and all the limit switches and selector switches. So I took it out to the customers location and installed
the control circuit and it worked great. Spindle forward and reverse . YEA !!! Thank you Hobby Machinist ! ! ! for the electrical
schematic and info on the lathe.

Eric Kesinger
Good morning Eric, I found this thread and instantly took notice. I am in the same situation that you were in last year. I have the same lathe and am sorting my way through the electrics and controls. I am going to use a VFD for mine, but am finding it difficult to find a manual. Were you ever able to find any more information on your lathe? Any help would be greatly appreciated, Erik W
 
Electrical diagrams don't usually survive a commercial environment. This one is pristine and I'm including it here for the 7.5hp 2-speed 1740G.

View attachment 371266


Here is a nicely preserved electrical panel per the above:

View attachment 371271


Note for those installing a Rotary Phase Converter and if your diagram looks like the above:

Wiring RPC to Lathe Input:

T1-Black -> L1-Red (R)
T2-Red -> L2- White (S)
T3-White/Blue -> L3-Black (T) Manufactured Leg
Did you rewire the motor from 440 volt to 220 volt? I bought a sj1540g and need to set it up for 220volt 3phase. I have a 6 lead 3 phase 440volt 2 speed motor. I'm not clear on how this is to be done.
 

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My recollection is that you would need a 9 lead wire if it was a dual voltage.
 
Did you rewire the motor from 440 volt to 220 volt? I bought a sj1540g and need to set it up for 220volt 3phase. I have a 6 lead 3 phase 440volt 2 speed motor. I'm not clear on how this is to be done.
Mine was already set up with a 220V 3 phase motor. My guess is that you either need a new motor or a transformer.
 
Hello everyone,

I have a few questions about this machine.
1. Is there a place for me to download the drawing or have it emailed?
2. Did you find the new switches?
3. Are you still looking for the manual? I have a rough copy of it.

I've been working with Mighty machines trying to figure out the buttons and wiring. Unfortunately they are in California.
Not sure if I can post there info so let me know if you need it.

Also I've had to make my own and replace a few of the internal shifters. So if yall need one let me know

Jack
 
Hello everyone,

I have a few questions about this machine.
1. Is there a place for me to download the drawing or have it emailed?
2. Did you find the new switches?
3. Are you still looking for the manual? I have a rough copy of it.

I've been working with Mighty machines trying to figure out the buttons and wiring. Unfortunately they are in California.
Not sure if I can post there info so let me know if you need it.

Also I've had to make my own and replace a few of the internal shifters. So if yall need one let me know

Jack
The electrical diagram is just a jpg (but decent quality) so you should be able to click and save the full version.

The guy with the switches never responded with model numbers (wish he would).

As for a copy of the manual, I'd LOVE to get it on here. If you can scan and save as a pdf we'd all be super appreciative!
 
Hello everyone,

I have a few questions about this machine.
1. Is there a place for me to download the drawing or have it emailed?
2. Did you find the new switches?
3. Are you still looking for the manual? I have a rough copy of it.

I've been working with Mighty machines trying to figure out the buttons and wiring. Unfortunately they are in California.
Not sure if I can post there info so let me know if you need it.

Also I've had to make my own and replace a few of the internal shifters. So if yall need one let me know

Jack
If you've got any pics or video on repairs and servicing that would also be super handy for folks that have these machines.
 
The electrical diagram is just a jpg (but decent quality) so you should be able to click and save the full version.

The guy with the switches never responded with model numbers (wish he would).

As for a copy of the manual, I'd LOVE to get it on here. If you can scan and save as a pdf we'd all be super appreciative!
I'll try and do it this weekend. It looks like the switches were made by tend tech.
They are in the other side if the world, but I've emailed them.
I'll let you know tomorrow or Monday
Here is who made the ones for my machine
Tend tech
 
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