1MAC309294-MB F Section 9
Other functions
RER620 427
Technical Manual
9.1.3.2 Battery management
Battery management consists of three functions:
• battery test
• battery charging
• battery start
Battery test
This function tests the battery's charge and overall health by briefly connecting a low
resistance load parallel to the battery and then measuring the battery voltage. The battery
voltage before the load was applied and the voltage during the time the load is applied may
be compared to determine battery's health. The load is about 1.5 ohms. The connection
time for the load is 0.1 seconds. Ten voltage measurements are taken and averaged
together in the last 25 milliseconds of the test period to calculate the battery voltage test
measurement. After the battery is tested, a cool down period of around 2 minutes for the
UPS's battery load resistors is required. During the cool down period the battery test
function is blocked
If the battery test function is blocked, the output channel "Battery Tested OK" of ZBAT1
function will be FALSE. If the battery function is blocked, the battery test voltage will be
zero. The measurements taken during the battery test may be read only once. Then the
measurements are zeroed.
Battery charging
The battery charger is designed to charge a 48 Vdc lead-acid battery. The charger has
maximum charge wattage of 40 watts. But the charge is firmware controlled in such a way
that the full charging wattage is applied only when the battery’s voltage is in the range 30
to 48 Vdc. At the lower end of this range, it is not known whether the battery is very
discharged or the battery is defective. If the recloser is operating off batteries, then the
system is switched off when the battery voltage reaches about 40 Vdc, so the battery
voltage should never be below 40 Vdc. At around 48 to 50 Vdc, the battery charge current
is decreased to start the transition to a float or trickle charge mode.
The maximum charge voltage is dependent on temperature. If the batteries are at a high
temperature the maximum charge voltage is decreased. At lower temperatures the
maximum charge voltage is increased. At room temperature the battery charge voltage is
about 55 Vdc.
The boost function has priority over the battery charger. When the UPS is in boost mode
the battery charger is off.
Battery start
The UPS has a function that will start the RER620-controlled recloser system if the battery
is charged to a voltage of about 44 Vdc. In order to start the UPS using battery power, the
power switch S1 must be pressed and held for about five seconds. Once operating using
battery power, the RER620 will continue to operate until the battery voltage discharges
down to about 40 Vdc, at which time the UPS will disconnect the battery from the system.
To Next Page
Loading...
Need help?
General
