Speed Control Devices for Danfoss BD 35 and BD 50 Compressors
Overview
The Danfoss BD 35 and BD 50 compressors have variable speed capability between 2,000 RPM and 3,500 RPM. If a
Danfoss BD 35 or BD 50 compressor is controlled by a standard thermostat it will run at 2,000 RPM only, but by
adding resistance to the circuit the compressor RPM can be raised . Operating a compressor at the slowest
possible speed results in longer run times but greater overall efficiency, and hence lower power consumption.
Water cooled systems with a pump, and holdover systems do not benefit from the compressor being operated at
a low speed, and these systems should normally be operated at high speed only. Coastal offers three speed
control devices.
SPEED BOARD
This is a secondary circuit board that is mounted with female connectors onto the Danfoss
101N0210 controller. The Speed Board provides the operator with the means to vary
compressor speed by means of a potentiometer (pot). This is adjusted by the operator with a
small screwdriver, and once set the compressor will always run at that speed unless readjusted. There is also a 12-24 switch that provides for a lower voltage cut-off if the system is
operated on 24v.
AEO CONTROLLER
The Danfoss AEO controller replaces the standard 101N0210 controller on the BD 35 and BD
50 compressors. This controller uses Adaptive Energy Optimization (AEO) to monitor
thermostat operation and adjust compressor speed in order to achieve a run time of 30
minutes. There is also a safety-start feature that ramps up compressor RPM gradually from
medium speed at initial start-up. This safeguards the electronics from overload.
SMART SPEED CONTROL (SSC)
The Frigoboat SSC comprises of a remote display panel and connecting cable.
The connections are made at the controller on a BD 35 or BD 50 compressor
and the remote panel can be flush mounted in a location where it can be
monitored and accessed. Like the AEO controller, compressor speed is
adjusted by the SSC according to thermostat operating frequency. Longer run
times are obtained by the SSC than with the AEO Controller, and hence
greater efficiency is achieved. The remote panel gives visual indication of
compressor speed and operational status, and a button is provided to enable
the SSC to be operated in either “AUTO” or “MANUAL” mode, and for initiating fast cool-down when re-stocking,
etc. Also included on the display panel is a diagnostic LED to aid in troubleshooting.