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Drilling Rig Electrical · Ross Hill / NOV

Ross Hill AC Control Module

The AC firing and protection module in Ross Hill and NOV SCR drilling systems, part 0521-2500-14. Surplus, replacement, and cross-referenced. Send the number and we'll tell you what we can find.

The Ross Hill AC control module manages the AC side of the SCR drive, firing the SCRs and handling protection logic for the power that runs the drawworks, mud pumps, and top drive. It's a control board on Ross Hill Controls and Hill Hayes SCR systems, now part of NOV, and it's increasingly obsolete. We source new old stock, surplus, and cross-referenced replacements.

Part numbers

OEM / Common P/NEI ReferenceDescription
0521-2500-14EI-0521-2500-14Ross Hill / NOV AC Control Module (SCR)
521250000EI-521250000AC Control Module, SCR drilling control
0521-2500EI-0521-2500AC Regulator / Control Module, Ross Hill SCR series

Numbers shown for reference and cross-reference. Confirm the exact part and revision against the nameplate before we quote.

Most SCR drives use the AC module as a matched pair with the Ross Hill DC Module (0522-2400-23). When one fails, it's often worth sourcing both.

Ross Hill & NOV, one SCR lineage

NOV acquired Ross Hill Controls and the Hill Hayes SCR designs. Most AC control modules kept their original Ross Hill numbering, so in most cases the NOV part number and the Ross Hill part number are the same. We cross-reference both directions and verify the pairing before quoting.

Frequently asked

What is the Ross Hill AC control module?
It's the AC firing and protection board in a Ross Hill / Hill Hayes / NOV SCR drilling drive, commonly part 0521-2500-14. It works alongside the DC module to run the drawworks, mud pumps, and top drive.
Is the Ross Hill AC module the same as the NOV AC module?
In most cases, yes, NOV kept the original Ross Hill numbering on the AC modules. Confirm the configuration and revision and we'll match it.
What's the difference between the AC and DC module?
The AC module (0521-2500-14) handles AC firing and protection; the DC module (0522-2400-23) handles DC regulation. They're a matched pair and both are usually required.
Can you supply a replacement?
Yes, new old stock, surplus, and cross-referenced replacements. Send the part number and we'll tell you availability and lead time.

Need a Ross Hill AC module?

Send 0521-2500-14 (or your number) and we'll tell you what we can find.

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