< Previous | Contents | Next >
EV.6.6.1 The Accumulator must contain a Precharge Circuit. The Precharge Circuit must:
a. Be able to charge the Intermediate Circuit to minimum 90% of the Accumulator voltage before closing the second AIR
b. Be supplied from the Shutdown Circuit EV.8.1
c. Not be fused
EV.6.6.2 The Intermediate Circuit must precharge before closing the second AIR. The end of precharge must be controlled by one of the following two options:
a. Feedback by monitoring the voltage in the Intermediate Circuit
b. A conservative time defined by the longer of:
Twice the time to charge to 90%
The time to charge to 90% plus 500ms
EV.6.6.3 The Tractive System must contain a Discharge Circuit. The Discharge Circuit must be:
a. Wired in a way that it is always active when the Shutdown Circuit is open
b. Fail safe such that it still discharges the Intermediate Circuit capacitors if the HVD has been opened
c. Not be fused
EV.6.6.4 If a Discharge Circuit is needed to meet EV.8.2.2.c, the Discharge Circuit must be designed to handle the maximum discharge current for minimum 15 seconds.
EV.6.6.5 Positive Temperature Coefficient (PTC) devices must not be used to limit current for the Precharge Circuit or Discharge Circuit
EV.6.6.6 The precharge relay must be a mechanical type relay.