BWDK-S is a dry-type transformer temperature controller (thermostat) produced by Fuzhou InnoTech, using microprocessor control, using three platinum resistors as sensors, used to measure the temperature of three-phase windings of dry-type transformers, and according to the set temperature value of the start and stop fans for temperature control, in line with the standard JB / T7631-2005, is the protection of dry-type transformers is an important device.