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Specialties

SCR & DC Drive Systems

SCR modules, DC regulators, and power stacks for legacy drive systems still running in the field.

SCR and DC drives ran heavy industry for forty years, and plenty are still turning motors today. The control modules, regulator boards, and power stacks that keep them running are increasingly obsolete — we source them and cross-reference to available equivalents. Send the part number and we'll tell you what we can find.

Independent sourcing, not an authorized distributor. We supply new-surplus, used-tested, and reconditioned drive parts, with condition disclosed before sale.

What we source

TypeNotes
SCR drive modulesFiring boards, assignment, and control modules
DC regulators / controlsSpeed and current regulator boards
Power modules & stacksSCR / thyristor power stacks and bridges
DC drive systemsGE, Ross Hill / NOV, Reliance, and other legacy lines

How an SCR / DC drive works

AC inputBus from diesel engine–generator sets, commonly 600 V AC
ConversionPhase-angle-controlled SCR (thyristor) AC-to-DC
DC output0–750 V DC, stepless
Per-SCR currentabout 1600 A continuous, typical
Assignable toDrawworks, mud pumps, and rotary table
ControlAC firing / assignment module plus DC regulation module (handwheel / throttle setpoint)

Typical SCR drilling-system values; configurations vary by rig. Verify against the equipment.

For the oilfield side of SCR drives, see Drilling Rig Electrical — Ross Hill / NOV control modules, SCR bay parts, and power modules.

Condition & sourcing

We supply SCR and DC drive parts as new, new-surplus, used-tested, and reconditioned, with condition disclosed before sale and photos on request. We are an independent surplus and sourcing company, not an authorized distributor.

FAQ

What drive systems do you cover?
Legacy SCR and DC drives from GE, Ross Hill / NOV, Reliance, and others, plus the firing boards, regulators, and power stacks inside them. Send the board or module number and we will source or cross-reference it.
Do you handle the Ross Hill drilling drives here too?
Yes. The drilling side has its own pages, where we cover Ross Hill / NOV control modules, SCR bay components, and power modules in detail.
Can you supply obsolete SCR firing boards and power stacks?
Yes, as new-surplus, used-tested, and reconditioned. The thyristor stacks and firing boards are the parts that most often fail and the hardest to find; that is exactly our lane.
Are you an authorized distributor?
No. Edmundson Industrial is an independent surplus and sourcing company, not an authorized distributor. Condition is disclosed before sale.

Request a Quote

Request a Quote

or send the part number to sales@edmundsonindustrial.com · (832) 975-8827 · Houston, TX. Same-day response on most requests.

Related

Send the SCR module or board number and we'll tell you what we can find.

Condition disclosed before sale. Same-day response on most requests.

Request a Quote