Overvoltage Solutions COMMON BUS DIODE SELECTION Bonitron > Products > Common Bus > Diodes

M3354D Isolation Diode

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.

Why Common DC Bus?
Why Common DC Bus?

M3345CBM Common Bus Sharing Schematic

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


  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.
  3 HP 5 HP 3 M3345CBM-10H3 10A 30A 30A 8.50" x 8.50" x 5.50"  
6 M3345CBM-10J6 60A
  10 HP 20 HP 3 M3345CBM-30H3 30A 90A 30A 8.50" x 8.50" x 5.50"  
6 M3345CBM-30J6 180A
  20 HP 40 HP 2 M3345CBM-60L2 60A 120A 50A 13.00" x 12.00" x 8.00"  
3 M3345CBM-60L3 180A
  20 HP 40 HP 4 M3345CBM-60P4 60A 240A 100A 15.00" x 24.00" x 8.00"  
6 M3345CBM-60P6 360A
  30 HP 60 HP 2 M3345CBM-90N2 90A 180A 100A 14.00" x 15.00" x 8.00"  
3 M3345CBM-90N3 270A
  100 HP 200 HP 2 M3345CBM-200P2 200A 400A 200A 15.00" x 24.00" x 8.00"  
  75 HP 150 HP 1 M3345CBM-200X1 200A 400A 200A 13.75" x 6.90" x 9.25"  
  100 HP 200 HP 1 M3345CBM-250X1 250A 375A 250A 13.75" x 6.90" x 9.25"  
  125 HP 250 HP 1 M3345CBM-300X1 300A 600A 300A 13.75" x 6.90" x 9.25"  
  125 HP 250 HP 1 M3345CBM-350X1 350A 450A 300A 13.75" x 6.90" x 9.25"  
M3460D Isolation Diode Schematic

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


  Made in the United States of America

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