Chromalox MaxPac, User Manual, Page: 23 / 44

21
SW3
Position Selection Note
0 Reserved for factory use Do Not Use this Selection
1 DOT for MXPCI Caution: Do not choose this setting if your unit is a
MXPCII or MXPCII type
2 DOT for MXPCII Caution: Do not choose this setting if your unit is a
MXPCI or MXPCII type
3 DOT for MXPCIII Caution: Do not choose this setting if your unit is a
MXPCI or MXPCII type
4 Time Proportional for MXPCI Caution: Do not choose this setting if your unit is a
MXPCII or MXPCII type
5 Time Proportional for MXPCII Caution: Do not choose this setting if your unit is a
MXPCI or MXPCII type
6 Time Proportional for MXPCIII Caution: Do not choose this setting if your unit is a
MXPCI or MXPCII type
7 Reserved for factory use Do Not Use this Selection
LED Indicators
LEDs and their function are as follows:
Designator Name Description
LD2 Output Demand Indication This LED blinks on according to the switching of output
LD3 Switch SCR1 OFF in normal operation. Turns ON if shorted SCR is detected
in one direction. Blinks rapidly if phase voltage is not present or
if SCR is shorted in both directions.
LD4 Switch SCR2 OFF in normal operation. Turns ON if shorted SCR is detected
in one direction. Blinks rapidly if phase voltage is not present or
if SCR is shorted in both directions.
LD5 Switch SCR3 OFF in normal operation. Turns ON if shorted SCR is detected
in one direction. Blinks rapidly if phase voltage is not present or
if SCR is shorted in both directions.
Alarm Output
The form C contact at J14 will be in the alarmed state in any of the following conditions:
• If any shorted SCR is detected. One or more of the shorted SCR LEDs LD3-LD5 will be lit in this case
• If missing Zero Cross transitions are detected at the SCRs. Typically, this is caused by missing power on
one or more phases, or from incorrect detection of phase sequence. One or more of the shorted SCR
LEDs LD3-LD5 will be blinking in this case
• If sensed temperature of the heat sink at an SCR junction exceeds 200 degrees Fahrenheit or 93 degrees
Celsius. The Overtemp output will also be engaged in this case.
• If sensed phase sequence does not match the setting of selector SW3. (Normally, SW3 should be left in
its factory-set state. See caution in section titled, “Phase Selection and Firing Mode“).