Common Bus

Common Bus Diode Selection


Common Bus Diodes are used to tie multiple drives to a common DC bus. Bonitron offers two styles.

Sharing Diodes

If drives on the AC line are connected by a DC bus, circulating currents can be created that might cause drive faults. Sharing diodes allow a two way flow of power to and from drives, enabling them to share power between their DC busses, while preventing circulating currents. The two-way flow allows the drives to share power with each other or use a common braking, regen, or UPD (Uninterruptible Power for Drives) unit.

Isolation Diodes

Unlike sharing diodes, isolation diodes allow only a one-way flow of power and do not allow drives to share power with each other, completely isolating the drives and preventing circulating currents. The isolation diodes allow multiple drives to be connected on the DC bus so that they can share one UPD. The M3460D allows inward flow of power so that one UPD can power all of the drives connected to the DC bus.

RoHS Compliant


Common bus systems with more than one power supply or input bridge can have circulating currents that cause overheating and drive faults. The M3345CBM allows more than one AC bridge to share on a common bus through back to back diodes, giving the advantages of power sharing between drives, while isolating the input bridges. This allows standard drives to be used in common bus systems without a single input supply.

  • Up to 200A
  • Prevents circulating currents in parallel bridges
  • Allows the use of one RideThru, Braking, or Regen Module with multiple drives
M3345CBM Schematic
Nominal HP Max. # of Drives
(per unit)
Model Number Drive Current Output Current Dimensions
(H" x W" x D")
230-240 VAC 460-480 VAC Peak Cont.

Bonitron’s M3460D Diode Sharing Modules provide blocking diodes that isolate the drives from each other while still establishing a shared, common RideThru DC bus. This can be used on equally sized and loaded drives within a system, allowing the use of a single Voltage Regulator with more than one drive.

  • Isolate drives while sharing common RideThru bus
  • Undervoltage Applications
  • Diode isolation protects individual drives
M3460D Schematic
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