Osama Sr 1740G Electrical Diagram

[MtnBiker]

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.




Here is a nicely preserved electrical panel per the above:




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

 

[Ulma Doctor]

Just to be clear....
under no circumstances should the manufactured leg supply the transformer.

by the diagram phases S and T will receive L1 and L3 as you described

 

[MtnBiker]

I'm not a wiring expert by any means - looks like transformer is fed from R(L1) to the 220V with S(L2) - the manufactured leg, to the 0V. I'm not familiar with the 0V notation but guessing that is the other side of the AC circuit. Assuming that is incorrect per you post above?

 

[mksj]

Exceptionally clean electrical enclosure. In the ROW they do not use split phase, so single phase AC would be between 0V and 220V (this is the usual convention for transformers). The transformer can be tapped for different input voltages that normally would be between two legs of the incoming 3 phase power. The transformer input connections 0V and 220V must not be connected to the RPC generated (wild) leg. You can either trace the wiring back to the input terminals or in some cases you can disconnect the transformer end and use an ohm meter at the input terminals. Per the wiring diagram R and S are connected to the transformer, T is not and would be the wild leg.

I appears that you have a 2 speed motor. Also there is no input fusing, so you would want your supply line to either be fused or the breaker sized for the machine, which I think you indicated in your RPC post.

 

[MtnBiker]

Exceptionally clean electrical enclosure. In the ROW they do not use split phase, so single phase AC would be between 0V and 220V (this is the usual convention for transformers). The transformer can be tapped for different input voltages that normally would be between two legs of the incoming 3 phase power. The transformer input connections 0V and 220V must not be connected to the RPC generated (wild) leg. You can either trace the wiring back to the input terminals or in some cases you can disconnect the transformer end and use an ohm meter at the input terminals. Per the wiring diagram R and S are connected to the transformer, T is not and would be the wild leg.

I appears that you have a 2 speed motor. Also there is no input fusing, so you would want your supply line to either be fused or the breaker sized for the machine, which I think you indicated in your RPC post.

Yes - the disconnect is fused for 25 amps.

Appreciate the info mksj. This forum is completely awesome!

 

[Eskideas]

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

Hello Sir

Thank god for you and you pics of the Osama Sr lathe. I am trying to repair a lathe out in Denver Colorado and you schematic helped me sooooo vey much. Do you have a operators manual for this lathe.??? I need to know the functions of the push buttons on the front and their functions. I think I know but need to confirm. (T) is Jog spindle?? Do you know by chance>>>>??? Please contact me , or post on the blog. I not familiar with Blogs and how they work. I run a independent machine tool repair service in Denver Colorado. E.S.K. Industries. I did find a electrical schematic glued to the cover of the electrical , but it was soaked with oil and not legible. Could send me a quick email of what the functions are on the operators buttons and switches on the front of the machine. Right now I am guessing ! Thank you So much Eric

 

[MtnBiker]

Hello Sir

Thank god for you and you pics of the Osama Sr lathe. I am trying to repair a lathe out in Denver Colorado and you schematic helped me sooooo vey much. Do you have a operators manual for this lathe.??? I need to know the functions of the push buttons on the front and their functions. I think I know but need to confirm. (T) is Jog spindle?? Do you know by chance>>>>??? Please contact me , or post on the blog. I not familiar with Blogs and how they work. I run a independent machine tool repair service in Denver Colorado. E.S.K. Industries. I did find a electrical schematic glued to the cover of the electrical , but it was soaked with oil and not legible. Could send me a quick email of what the functions are on the operators buttons and switches on the front of the machine. Right now I am guessing ! Thank you So much Eric

Have been looking for the original manual and no luck yet.

These are the functions for the two speed motor versions (top to bottom):

Top switch is jog (specifically for use on feed/threading gear box)
Second "button" is power indicator light.
Third switch is main power.
Fourth switch is the low/high power settings on the motor.
Fifth switch is on/off for flood coolant pump.

Note, there is an extra 110v circuit that terminates into the coolant tank. Intended for a worklight. On two-speed models there is no panel switch for this circuit. On single speed versions, there is a panel power switch.

Hope that helps.

 

[Eskideas]

Thank you very much for the information. Thant helps very much! I wish i had a electrical schematic not just a electrical layout.
I am going to try and duplicate the inputs from the limit switches and get the control electronics working before I take it out to the
customers shop way on the other side of town. Thank you for your help. Eric

 

[MtnBiker]

Thank you very much for the information. Thant helps very much! I wish i had a electrical schematic not just a electrical layout.
I am going to try and duplicate the inputs from the limit switches and get the control electronics working before I take it out to the
customers shop way on the other side of town. Thank you for your help. Eric

Best of luck on the repairs. If you need to do replacements of anything, let me know about any compatible parts so we can save someone the hassle of sourcing.

 

[Eskideas]

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