Safety And Protective Functions; General - Sevcon Gen4 Applications Reference Manual

Safety and protective functions

General

WARNING: Electric vehicles can be dangerous. All testing, fault-finding and adjustment
should be done only by competent personnel. The drive wheels should always be off the
floor and free to rotate during the following procedures. The vehicle manufacturer's
manual should always be consulted before any operation is attempted.
WARNING: The battery must be disconnected before replacing the controller. After the
battery has been disconnected, wait 30 seconds for the internal capacitors to discharge
before handling the controller.
WARNING: Battery vent caps must be securely in place before connecting the controller
to a battery as an arc may occur due to the controller's internal capacitance when it is first
connected.
WARNING: If a PMAC motor is being used at the maximum motor speed the peak line to
line back emf must not exceed the non-operational voltage limit specified in (add ref to
section 4 input voltage table). The controller may be damaged if the back emf exceeds
this level.
WARNING: Do not tow vehicles that have PMAC motors, the motors act as generators and
may cause high currents to flow in the motor, controller or battery system. If towed at a
speed in excess of the vehicle rated speed the voltage generated by the motor may
damage the controller or battery.
WARNING: When a PMAC motor is acting as a generator, for example when braking or
driving down hill, the short circuit current must not exceed the controller current rating.
The short circuit current should be calculated for all vehicle speeds and must be less that
the controller current rating. If the current is greater than the controller current rating then
measures must be taken to protect the controller from the motor acting as a generator.
Possible measures include adding a disconnect switch between the motor and controller
on at least 2 out of the 3 phases, or adding fuses in each phase. Contact your local
Sevcon representative for further information and guidance.
CAUTION: Ensure that contactors with blow-out magnets are wired with the correct polarity to
their power terminals as indicated by the + sign on the top moulding.
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