Rapid Pressure Rise Relay Adapter

A machined two-flange adapter that mounts a rapid pressure rise relay (also called a sudden pressure or fault pressure relay) to a transformer flange whose bolt pattern does not match the relay.

Made bySouthern Switch & Contacts

Part typeCustom fabrication · mounting adapter

ApplicationRapid pressure rise / sudden pressure relay mounting on power transformers

Barrel2.5″ Schedule 80 pipe · 4.5″ overall length

FlangesTransformer side 4.25″ sq on a 2.75″ bolt pattern · relay side 3″ sq on a 2.25″ bolt pattern

MaterialSteel as built for this order · machined to any material spec you require

AvailabilityBuilt to order / lead time confirmed at quote

What it does

A rapid pressure rise relay protects a power transformer by tripping on a fast rise in internal pressure from a developing fault, before the fault escalates. The relay only does its job if it can be bolted to the tank. When the relay’s mounting flange and bolt pattern do not match the fitting on the transformer, or when the original adapter is obsolete and no longer available, the relay cannot be installed or replaced without an adapter in between.

This part is that adapter. It carries a transformer-side flange on one bolt pattern and a relay-side flange on a different, smaller pattern, joined by a length of pipe. It reconciles the two bolt patterns and stands the relay off the tank wall by the barrel length so the unit clears the mounting face and seats square.

Dimensions

Machined from Southern Switch & Contacts drawings:

Barrel: 2.5″ Schedule 80 pipe, 4.5″ overall length
Flange plate: 0.5″ thick, welded to each end of the barrel
Transformer-side flange: 4.25″ square, four 9/16″ holes on a 2.75″ square pattern, 2.125″ through-bore
Relay-side flange: 3″ square, four 7/16″ holes on a 2.25″ square pattern

This adapter was built from steel. We machine it to any material you specify, so the material and finish are set to match your application at quote.

Built to your print

We build this adapter to a print, a sample, or the relay and transformer flange dimensions you supply. If the original adapter is obsolete or the relay and tank were never a matched pair, send the two bolt patterns and the relay port size and we machine a replacement that fits both.

Stock, lead time & reverse engineering

Lead time is confirmed at quote; discontinued or hard-to-find adapters are reverse-engineered from a sample, a drawing, or a model number. Based in Palm Harbor, FL, Southern Switch & Contacts manufactures and ships replacement parts to utilities nationwide, and has served the industry since 1982.