Hammond PWDP13188 Collins KW-1 T-401 Bias & Filament Transformer

The PWDP13188 is the Collins KW-1 bias transformer, reference T-401, described as the -150 volt DC bias and filament transformer. Built from the Peter W. Dahl design files, it is for restorers and technicians maintaining the Collins KW-1 transmitter.

The primary is 115 VAC, 60 Hz, single phase. Two secondaries are listed: S1 is 300 VCT @ 30 mA CCS for the bias supply, and S2 is 5 VAC @ 2 A CCS for filament service.

The transformer is wound on an EI-112 x 1.125 core and built in style 4 of the series style sheet. It is a compact unit with an approximate weight of 3 lb and a shipping weight of 3 lbs (1.36 kg). It is listed as REACH and RoHS compliant.

The PWDP13188 is listed for 60 Hz operation; the series notes advise buyers outside North America who need 50 Hz to select parts marked 50/60 Hz. PWDAHL Series transformers are usually built to order one at a time, so confirm availability by phone or e-mail before ordering. Identifiers include UNSPSC 39121301. The small EI-112 core and 3 lb weight reflect its low-current bias and filament duty.