B4-2WT tubular slip ring B-Series

B4-2WT: thin weatherproof tubular slip ring

The B4-2WT is a weatherproof tubular slip ring with four circuits rated at 1 A, only 20.07 mm (0.79 in) wide, against 32.11 mm for the B4-2W. It mounts on shafts up to 50.8 mm (2 in) in diameter and connects strain gages, thermocouples and other sensors on rotating equipment to the stator; its rings and brushes are made of precious metals, for low-level signals. Non-contact labyrinth seals, which do not wear out, protect it from water, mud, snow, dust and other contaminants, and its bearings are permanently lubricated. The stainless steel body is Ø 105.66 mm (4.160 in) and weighs 1.16 kg. It runs at up to 7,000 rpm, from −40 to 121 °C, with a maximum peak noise of 0.1 Ω (resistance variation across the contact).

The sensor wires reach the solder terminals of the rotor through wire path slots, two terminals per connection, the second one being a backup if the first is damaged. On the stator, a Bendix PT02E-8-4P connector, supplied with its PT06E-8-4S mating connector, can be replaced by a lower-profile terminal plate. The rotor is fastened with eight #6-32 socket-head set screws, and a bushing is needed on shafts smaller than 2 in. A Ø 4.76 mm through hole in the stator takes the restraint. The slip ring turns in both directions; units for continuous speeds above 7,000 rpm are special orders.

It is typically used for automotive drive shaft measurements in road testing, where the compact design suits limited space on the shaft.