[How do I?] Motor wiring puzzle

I am trying to help a friend get a motor wired up and it has me stumped. The motor is 5hp single phase 240v 3420rpm TEFC with a centrifugal switch for a start capacitor. It was purchased surplus with no documentation and missing capacitor(s). Here is the tag:
grizzly-motor.jpg
Grizzly has been no help.

There are two red wires, two black wires, and one yellow wire coming out of the motor.

R1 connects to one of the centrifugal switch contacts. It is open circuit to everything when the contacts are open. R2 connects to the other side of the
centrifugal switch. Simple enough but I have not been able to make sense of the connections to the windings.

I measured the following resistances between pairs (measured with 4-wire connections, variation in the contact resistance is about 0.01 ohm):
Bk1 -- Bk2 0.206 ohm
Bk1 -- R2 0.904 ohm
Bk1 -- Y 0.006 ohm
Bk2 -- R2 0.936 ohm
Bk2 -- Y 0.197 ohm
R2 -- Y 0.930 ohm

All of the wires are > 1500 Mohm to the case.

I would appreciate any insights or advice on how to proceed.

Dave
 
I agree that there is something screwy about the resistance readings so they have been checked multiple times. Measured with a HP 3468A
multimeter in 4-wire resistance mode. My confusion was even greater in the beginning since the centrifugal switch contacts had significant and non-reproducible resistance. Holding the switch open isolated R1 and resulted in the measurements listed. They are consistent with the following schematic:
View attachment 284225
Which doesn't match any that I have been able to find on the internet. It looks more like a multispeed motor but that would require an external connection to the junctions between L2 and L3.

Looks to me like BK1 and BK2 are the line connections and the start capacitor should be connected between R1 and Y.
R2 is possibly for a run capacitor but if the other end is connected to either line then running current would flow continuously through the high resistance winding L1 and the current through the two halves of the main winding would be unbalanced. With 240V at 25A I don't want to get it wrong--the magic smoke release could be exciting.

There is no wiring diagram in the junction box. The motor is at my friends place. I'll get some photos of the wiring tomorrow.
Wired it up last night with a 300 uF start capacitor at R1-Y and it spins up very nicely, draws 13.5 A with no load. Don't have any way to test it under load so I can't tell if adding a run capacitor has any effect. It seem happy with 30 uF between R2 and BK1. Nothing gets hot.

Thanks to all for your help.

Dave
 
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