Contactor Chopping - Sevcon MillipaK 4QPM Manual

Configuration
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Contactor chopping

This feature allows 24 V contactors to be used at all battery voltages 24V - 48V, by continuously
monitoring the battery voltage and chopping the contactor output pins accordingly, to present an
average voltage suitable for 24V coils. Chopping is selectable by the calibrator. Care must be
taken to ensure that chopping is always selected if 24V contactors are being used on battery
voltages higher than 24V. In applications > 24 volts contactors must be fitted with blow out
magnets. Chopping can reduce the overall dissipation in the coils and allows only one set of
contactors to be stocked for all battery voltages.
Chopping Frequency approx.
Typical contactor coil voltage during chopping
Typical contactor coil voltage during energisation
There are 3 contactor chopping options available via the setup menu: Off, On and 24V. The off
setting is used for nominal battery voltage coils, and the On setting is for 24V coils on higher
voltage vehicles. Setting to 24V provides chopping for 24V coils and lamps without the drop to
16V after 1s.
Chop Select
Calibrator Menu Reference:
Options
OFF ON
MillipaK 4QPM Controller Manual
Power Up
12.01
Default
24V OFF
= 667Hz (Slightly audible).
= 16 volts.
= 24 volts for 1 second.
Page 24
System/Contactor Chopping
13/08/03