The Bonitron M3728 DC Inrush Limiter safely precharges a drive or other
capacitive loads from a DC source, such as a diode rectifier or battery bank.
When the M3728 is powered off or disabled, there is no path between the
source and the capacitive load. When the unit is enabled, a resistor charges
the capacitive load slowly. When precharge is complete, the resistor is
removed from the circuit, allowing the load to operate normally. The M3728
also has a status contact that indicates when the capacitors are fully charged;
this can be wired in series with the drive enable signal for easy integration.
Additionally, care must be taken to protect battery strings, as they can
be damaged by discharging them below their safe minimum voltage.
Such damage often requires expensive refurbishment or replacement. In
situations where M3728 is fed from a battery string, the unit can be set to
disconnect the load if the battery voltage falls to a preset level.