The FK-50P uses the same control board as the FK-35, but with upgraded outputs and driver circuit, a multiturn, clutched, hermetically sealed potentiometer is utilized in lieu of jumpers for precision temperature setting.

What size controller do I need

Our controllers are rated byway of their nomenclature to indicate their current capability, as an example, an FK35 is capable of providing 35A of continuous current, these ratings are given in consideration of reliable operation under real world environmental conditions, so there is no need to under rate the application. In other words, a cooling fan that consumes 35A of continuous current requires the use of an FK35 controller, and although a 60 series controller may be substituted, there is no real benefit in doing so.

My fan has a peak current draw of 105 Amps, will this controller work with my fan?

An electric motor generates its own voltage when rotating under load that is typically about two thirds the input voltage, this generated voltage reduces the effective voltage applied to the motor windings by a factor of three and the reduction in voltage lowers the running current by the same amount. When a voltage is applied to a non-rotating motor, this voltage is not generated, and the effective voltage and current are not reduced, so when full input voltage is applied to a non-rotating motor, a non reduced or peak current occurs until the motor attains the working rotational velocity. The Delta controller ramps the voltage up slowly, avoiding locked-rotor current conditions. Moreover, although the Delta controller output devices have a peak current rating in excess of 400A, the controller is internally current limited to 50A short term in order to regulate peak currents and 35A long term in order to protect a shorted or dragging fan. In other words, the peak current specification of the fan doesn't need to be considered when choosing a controller.