Specifications

POWERCASSETTE FRONT-END

OPERATING MANUAL

tested in Position A (left side) of the rack.

18.2 With the input power source turned off, connect input power wires to the

PowerCassette mating connector or in case of the rack to the input connec-

tor on the A side of the rack. Make sure that the safety ground wire is con-

nected. Do not touch the output terminals when AC input power is present.

18.3 Connect a resistive power load across the proper output pins. The load

should be 20% to 50% of full load value and can be either a power resistor or

electronic load set to the resistive mode. Make sure that the power resistor

has adequate heat sinking and cooling.

18.4 Connect a color-coded, twisted pair (no. 22 or 24 AWG) from the remote

sense pins on the mating connector to the load. The +Sense pin must go

to the positive side of the load and the -Sense pin to the negative side

of the load. Also connect the Enable pin, pin 27 of the Positronics

mating connector of the PowerCassette, to the - Sense, pin 9. This

must be done for the unit to operate. When using the rack, the Enable pin

is automatically connected to - Sense in the rack. The units are then con-

trolled by the Inhibit inputs.

18.5 Checking Front Panel LEDs. With the PowerCassette on the bench or in

Position A of the rack, turn on (or plug in) the power source. The AC Power

Fail (bottom left) green LED should be on and the DC Power Good (bottom

right) green LED should also be on.

18.6 Checking the Output Voltage. Measure the output voltage at its load with a

digital voltmeter. The voltage should be within ±1% of its nominal value.

18.7 Checking the Inhibit Input. Unplug the input power source. Connect a wire

from the Inhibit input (pin 10 on the PowerCassette Positronics connector ) to

- Sense, pin 9.

Turn the input power source back on. The AC Power Fail green LED should

turn on but the DC Power Good green LED should remain off. Check the

output voltage with a digital voltmeter. It should read zero volts.

18.8 Checking the AC Power Fail and DC Power Good Signals. Next check

the voltage on the AC Power Fail pin (pin 15 on the PowerCassette

Positronics connector) with respect to - Sense (pin 9 ). The voltage should be

a logic LO, +0.5V or less. Finally, check the voltage on the DC Power Good

pin (pin 14) with respect to - Sense (pin 9 ). The voltage should be a logic HI,