M3800 Capacitive Regen Controller

M3800 Capacitive Regen Controller

Bonitron's Capacitive Regen Controller is a simple, passive method for storing regenerated energy from a braking motor, well suited for cyclic applications.

The M3800 Capacitive Regen Controller, used in conjunction with a capacitor bank and various external components, allows for an increase in energy storage with a smaller rise in DC bus voltage. This stored energy can then be sourced back onto the DC bus during periods of higher demand, lowering the peak power required by the drive system.

For use on repetitive motion / cyclic applications such as Punch Presses, Eccentric Loads, and Pump Jacks.

M3800 Specs
System Layout

The M3800 Controller, as part of a Capacitive Regen system, requires several external components. Please see below for a diagram of the expected external system layout.


The same resistors used for precharge can be used to discharge the capacitor bank. There also needs to be a contactor in the discharge path, however this should be a Normally Closed contactor. This way, if power is removed from the system, it automatically discharges the capacitor bank to a safe voltage.


The capacitors must be sized according to the voltage and joule requirements of the application. They must be able to absorb the regenerated energy from the drive and keep the voltage below the drive's overvoltage fault level.

Output to drive

The output contactor must be rated for the max DC bus voltage as well as the max expected regen current.


The M3800 must be able to precharge the storage bank before it can connect to the drive bus, requiring a rectifier and resistor with a contactor to control them.

M3800 external components

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