Contactors

Contactors used for both safety and high voltage switching. They are basically a heavy duty relay used to switch the high dc voltage that is derieved from the main battery. They are used for the motor drive, the heating and cooling systems, the DC-DC converter, the charger and anything else that draws more than a few amps from the main battery.

With the MX-5e we plan to use the following contactors:

  1. Motor contactor - used to connect the positive supply to the motor. The motor is disconnected when the battery is being charged.
  2. Main negative contactor - used in the negative supply from the main battery (after the main fuse). This is a 'belt and braces' approach to ensure the battery is completely isolated. It is also a fail-safe just in case the positive contactor does get arc welded shut.
  3. Main precharge contactor - used in the positive supply from the main battery to reduce contact arcing.
  4. Main positive contactor - used to connect the positive supply from the main battery.

The contactors are enabled in this sequence to prevent damage.