I need assistance in identifying a semiconductor component in a High / Low speed control circuit for a floor buffer machine. Heres what I know as fact since I have another "working" machine and am trying to reverse engineer the circuit.
The motor ia 1.5 HP. it is fed from a bridge rectifier.The bridge rectifier is fed directly from the 120 VAC supply in the high speed mode (150 VDC output). In low speed mode (75 VDC output) a thyristor circuit is introduced in series between the 120 VAC supply and the bridge rectifier. The thyristor circuit consists of the following (4) components: (1) 56K RESISTOR, (1) .1uF "104K" CAPACITOR, (1) LINE THYRISTOR "Semikon # SKT40/16E", and (1) unknown semiconductor that feeds the gate of the thyristor. Three of the components (thyristor, resistor, capacitor) are installed in the circuit and are working with the old semiconductor that feeds the gate of the thyristor. I am unable to identify either the type or properties of the "gate" semiconductor. The component in question is .150" long with a .070 diameter 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.
The working thyristor circuit and voltage readings are are follows:
A 56K resistor (120 VAC before resistor, 81VAC after resistor) is in series with a .1uF capacitor and inserted in parallel across the line "in/out" of the thyristor. The gate of the thyristor is supplied (72 VAC) through the unknown semiconductor which intersects the series circuit between the resistor and the capacitor (81 VAC). These voltage readings are from the working thyristor circuit. 120 VAC before the resistor, 81 VAC after the resistor but before the capacitor. Out of the unknown semiconductor and into the gate of the thyristor is 72 VAC. 72 VAC is also the reading exiting the thyristor and feeding the bridge rectifier.
I would appreciate help in identifying the "unknown semiconductor" and possibly it's required properties for the above mentioned circuit.
Thank you in advance.....
The motor ia 1.5 HP. it is fed from a bridge rectifier.The bridge rectifier is fed directly from the 120 VAC supply in the high speed mode (150 VDC output). In low speed mode (75 VDC output) a thyristor circuit is introduced in series between the 120 VAC supply and the bridge rectifier. The thyristor circuit consists of the following (4) components: (1) 56K RESISTOR, (1) .1uF "104K" CAPACITOR, (1) LINE THYRISTOR "Semikon # SKT40/16E", and (1) unknown semiconductor that feeds the gate of the thyristor. Three of the components (thyristor, resistor, capacitor) are installed in the circuit and are working with the old semiconductor that feeds the gate of the thyristor. I am unable to identify either the type or properties of the "gate" semiconductor. The component in question is .150" long with a .070 diameter 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.
The working thyristor circuit and voltage readings are are follows:
A 56K resistor (120 VAC before resistor, 81VAC after resistor) is in series with a .1uF capacitor and inserted in parallel across the line "in/out" of the thyristor. The gate of the thyristor is supplied (72 VAC) through the unknown semiconductor which intersects the series circuit between the resistor and the capacitor (81 VAC). These voltage readings are from the working thyristor circuit. 120 VAC before the resistor, 81 VAC after the resistor but before the capacitor. Out of the unknown semiconductor and into the gate of the thyristor is 72 VAC. 72 VAC is also the reading exiting the thyristor and feeding the bridge rectifier.
I would appreciate help in identifying the "unknown semiconductor" and possibly it's required properties for the above mentioned circuit.
Thank you in advance.....