Allis-Chalmers TLH-21 Isolated Rev Kit

Overview

Isolated reverser kit for the Allis-Chalmers TLH-21 load tap changer, all contacts and hardware of the standard kit plus the reversing switch contact finger support and reversing switch assembly. For LTCs requiring full reverser-side replacement.

About the Allis-Chalmers TLH-21

The Allis-Chalmers TLH-21 is a later-generation reactor-type load tap changer with an isolated reversing switch design that separates the reversing switch contacts from the main switching path, reducing reversing contact wear compared to earlier TL-series designs. The main moving and stationary contacts still require periodic inspection and replacement at the manufacturer's recommended interval. The TLH-21 is found in utility distribution and transmission transformers and is fully supported by Southern Switch with new contacts, complete kits, and hardware including the collector hub, collector ring, and reversing switch assembly.

Why replace worn LTC contacts

Worn or burned tap-changer contacts raise resistance, run hot, and can lead to tap-changer failure. Precision replacements restore reliable switching and extend the service life of the LTC.

Stock, lead time & reverse engineering

Common items are produced on short lead times; discontinued or hard-to-find parts 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.