Dramm - Speed Controller

Brand: Dramm

Speed Controller

A Variable Power-Station speed controller for Dramm AME horizontal air flow fans. It regulates the voltage supplied to the fans, so one knob takes a whole bank from a crawl to full output, and Dramm's own guidance is to hold AME fans at 40 to 60 percent of maximum for normal operation and open them up as the crop fills in and foliar mass starts blocking air movement. Running the bank slowly cuts energy use, reduces turbulence over the crop and stops a high speed fan from collecting and re-depositing pesticide. Amperage is the choice on this page, and it does two jobs at once: it sets how many fans one controller can carry, and it separates the knob-only 5 AMP unit from the analog Power-Station units above it.

Size the controller from your fan count first. Divide the controller's amp rating by the maximum current draw of the fan you are hanging - 0.9 amp for the AME 350mm (14 in) and 1.2 amp for the AME 400mm (16 in) - and round down. That puts 5 AMP at five 350mm fans or four 400mm fans, 6 AMP at six and five, 10 AMP at eleven and eight, and 20 AMP at twenty-two and sixteen. Then decide whether the bank has to answer to a climate computer. 5 AMP is the knob-only build: manual speed control, no analog input, and Dramm sells it as the lower cost controller for a grower who will run the house by hand. 6 AMP, 10 AMP and 20 AMP are all the same analog Power-Station and all carry the full feature set - a 2-10 VDC or 4-20 mA input selected by a jumper so a climate computer can drive fan speed and shut the bank off without a separate relay, a HAND / 0 / AUTO switch on the side where HAND is a full power bypass, minimum and maximum ventilation potentiometers on the main board so every fan in a circuit actually starts turning, protection against extreme electrical fluctuations, and an alarm output that trips on a power failure and reverts the controller to its manual setting so the fans keep running. So computer control does not mean stepping up to 10 AMP - the 6 AMP has all of it. Choose 6 AMP for a small computer-driven bank, 10 AMP or 20 AMP when the fan count or your planned expansion needs the headroom, and 5 AMP only when you are certain the house will never be automated.

Specifications

Configurations

Key Features

• One knob sets the speed of a whole bank of AME fans by regulating the voltage they receive
• 6, 10 and 20 amp builds accept a 2-10 VDC or 4-20 mA signal so a climate computer can drive the fans directly
• An analog signal below the low limit switches the bank off, so no separate contactor is needed
• HAND / 0 / AUTO switch gives a full power bypass for commissioning and fault finding
• Minimum and maximum ventilation potentiometers trim the voltage range so every fan in a circuit starts turning
• Alarm output trips on a power failure and reverts to the manual setting rather than stopping the fans
• 5 amp build is the low cost manual controller for a house that will never be automated
• Running a bank at 40 to 60 percent cuts energy use and reduces turbulence over the crop

Ideal Applications

• Matching AME fan speed to crop stage as foliage builds and blocks airflow
• Holding steady air movement to prevent condensation and foliar disease
• Slowing fans during a chemical application so the spray is not thrown around
• Manual control of a small fan bank with no climate computer
• Climate computer controlled air movement across a bank of any size
• Riding out rapid greenhouse temperature swings without cycling fans on and off

These controllers drive the Dramm AME 350mm and AME 400mm HAF fans, sold separately, and the guard sets for fans hung below 8 ft are listed on their own page.