Semiconductor Help

[CVCTF]

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I need assistance in identifying a semiconductor component in an electrical circuit (see attached) so I can duplicate this circuit. The circuit diagram drawn is of a physically existing, properly working circuit. The voltage readings I've noted were taken with the circuit energized in low speed mode with the proper low speed RPM. The component I'm trying to identify controls the gate of the thyristor. I am only assuming this is a DIAC. I need to verify this and determine the electrical characteristics so I can build it. The component in question is .150" long with a .070" diamater and two leads. it appears to be made of a glass type material and looks similar to a DIAC or a SIDAC. I have tried a SIDAC (NTE6415) and a DIAC (NTE6412) without success.
Once identified I also need to know the electrical characteristics, Vbo, etc...so I can replace this component in other circuits.

Any help would be greatly appreciated.

THANK YOU....

 

[Compositepro]

If you have 72 volts after your triac and your motor isn't turning, then you have a problem with your motor or bridge rectifier. A floor buffer would not use a D.C. motor so the bridge rectifier should be unnecessary, although a universal motor should work on D.C. This assumes that your motor is a universal motor and not an induction motor. Are there brushes on the motor? Also this forum is not for hobbyists, so don't expect your post to last long.

 

[CVCTF]

Thank you for your reply. Initially I would like to state that I am not a hobbyist. I am an electrician working at a facility trying to repair the High/Low speed controls on several floor buffers. I was deferring to this forum for help on identifying a particular semiconductor in the speed control circuit.
The attached diagram is the circuit from the speed control tryristor module I removed from a “working” unit. I am trying to reverse engineer this component so I can repair the others. I’ve identified all components in the circuit except one, that being the semiconductor that controls the gate voltage to the thyristor. I’ve given the physical description of the component and the voltage readings while the circuit was energized in low speed mode.
Lastly the motor information you provided is “invaluable” but irrelevant. The motor works properly in the test unit with the bridge rectifier as this is how the unit is shipped. This information is not available from the manufacturer. I was deferring to this forum for assistance.
Thank you in advance for your assistance.

 

[VEBill]

Post seems to be in-scope for the forum. The regulars here do tend to double-check for students and hobbyists to protect the integrity of the website.

Search Google Images for Light Dimmer Circuit and you'll see the same circuit architecture as you've posted. So the 2-terminal device should be a diac or something similar.

Perhaps there are multiple problems. The diac normally wouldn't fail unprovoked. It could be a cascade of failures.