BENSHAW RediStart MX2 SEP, Руководство пользователя

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RediStart MX
2
- SEP Synchronous Controller User Manual
106
8.5 SCR Testing
8.5.1 Resistance
The SCRs in the controller can be checked with a standard ohmmeter to determine their condition.
Remove power from the controller before performing these checks.
• Check L to F+ for each phase. The resistance should be over 50k ohms.
• Check L to F- for each phase. The resistance should be over 50k ohms
• Check between the gate leads for each SCR (red and white twisted pair). The resistance should be from 8 to
50 ohms.
NOTE: The resistance measurements may not be within these values and the SCR may still be good.
The checks are to determine if an SCR is shorted or if the gate in an SCR is shorted or open. An
SCR could also still be damaged even though the measurements are within the above
specifications.
8.5.2 Voltage
Extreme caution must be observed while performing these checks since the controller has lethal voltages
applied while operating.
Using a DC voltmeter, check between the gate leads for each SCR (red and white twisted pair). The voltage
should between 0.5 and 2.0 volts.
8.6 Field Discharge Resistor Sizing
The induced field voltage (product of induced field in amperes and discharge resistance in ohms) must be
between 200 and 1000 VAC at zero and 95% speed. When the motor is between 0% and 95% speed, there is
an AC voltage applied. After 95% speed, the DC field will kick in. Refer to the example below.
• Induced field current: 0% speed, 30 A; 95% speed, 17 A
• Recommended field discharge resistance: 25 ohms
• 25 ohm x 28 A = 700 V (zero speed check)
• 25 ohm x 15 A = 375 V (95% speed check)
The requirements are met for this example.
If the induced field voltage is greater than 1000 volts, contact the factory.