Exide Technologies JA5009-00 - Manual (Page 23)

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12. ZERO-CENTER DC AMMETER FOR BATTERY/LOAD MONITORING (EJ0138)
Purpose and Description: The zero-center dc ammeter (M7) lies within the negative return lead of the
battery. A current-sensing shunt (SH2) is provided when the range is greater than 50 Amperes. M7 indicates
the direction and amount of the battery current. Indication on the ammeter is to the right of center when the
charger is charging the battery and to the left when the battery is furnishing current to the load (discharging).
13. HIGH DC VOLTAGE CHARGER SHUTDOWN ALARM RELAY W/IND. LIGHT (EJ0592)
Purpose: The High DC Voltage Shutdown option functionally disables and locks-out the battery charger
whenever the output DC voltage exceeds the preset upper limit of charging voltage. This option is designed
to protect the batteries and/or load from an over-charge or over-voltage condition. In the case of parallel,
redundant chargers with charger shutdown, this option selectively detects and shuts down the faulty
charger/rectifier only. The option provides a front panel indicating light and alarm contacts wired to TB3
terminals 53, 54 & 55.
Description: The high DC voltage detector PC Board assembly (A13) is an HVA alarm module, which
closes a circuit on alarm and energizes the shutdown relay (K21). The shutdown relay disconnects the
Control Module (A1) from its AC supply thus removing the SCR trigger signals to the rectifier. This
disables the charger and output current goes to zero. After shutdown the circuit must be manually reset
before restarting the charger. A push-button “CHARGER RESET” momentary switch (SW14) is provided
on the front panel for this purpose. The high DC voltage detector circuit has a built-in, several second, time-
delay to prevent charger shutdown due to transient voltage surges.
Adjustment for the shutdown circuit is provided by a potentiometer (R4) on the A13 assembly. It can be
field adjusted using the same procedure as for the HVA portion of the EJ0083 option on page 14.
The factory-preset thresholds for HDCV charger shutdown are as follows unless otherwise specified:
2.40 volts/cell for LEAD ACID
1.65 volts/cell for NICKEL CADMIUM
The above set points are the same as the High DC Voltage Alarm (HVA). If HVA and High DC Voltage
Shutdown options are ordered on the same charger, the shutdown thresholds are set as follows unless
otherwise specified:
2.45 volts/cell for LEAD ACID
1.70 volts/cell for NICKEL CADMIUM
14. END OF DISCHARGE ALARM RELAY (EJ0143) - WITH OPTIONAL INDICATOR LIGHT
Purpose and Description: The End of Discharge alarm option utilizes a printed circuit board assembly
(A8) to provide low-limit threshold voltage, set at the lowest safe voltage to which the batteries may be
discharged. Alarm contacts are wired to TB3 terminals 31, 32 & 33. These may be used to operate a system
load disconnect circuit by tripping a shunt trip DC load circuit breaker or opening a DC load contactor. An
optional "END OF DISCHARGE" front panel indicator lamp (DS12) may also be provided.
The factory-preset thresholds for alarm condition are as follows unless otherwise specified:
1.75 volts/cell for LEAD ACID
1.00 volts/cell for NICKEL CADMIUM