Ruck MTP 40 Potentiometer in the Fan Terminal Box
The MTP 40 is a small rotary potentiometer that sets the speed of a Ruck EC fan. It is built to connect inside the fan's terminal box rather than on a wall. The resistance element is rated at 10 kOhm. Three black leads run from the potentiometer body. Ruck's wiring diagram marks them as ground, the 0-10V signal and the +10V supply. The fan's EC electronics feed that supply to one end of the element. Turning the shaft moves the wiper, and the wiper voltage becomes the speed signal. A lower voltage slows the motor, and a higher voltage speeds it up. The potentiometer body is 16 mm across, and the assembly is 115 mm long including the leads. It is rated for ambient temperatures up to 50°C, or 122°F. Ruck lists part number 147359 and a sales unit of 20 pieces. Sylvane lists it as an accessory for Ruck Axialine tubeaxial fans from 12 to 28 inches. The Ruck data sheet is attached.
Wiring an EC Fan Speed Potentiometer
Isolate power to the fan before opening the terminal box. Match each lead to the terminal markings in the fan's own wiring diagram. The ground, signal and supply leads land on the control terminals, never on the mains terminals. Mains voltage on these leads would destroy the potentiometer and could damage the fan electronics. Route the leads clear of moving parts and away from the motor housing. Close the terminal box and restore power. Start with the shaft turned low, then raise it until the fan reaches the airflow the room needs. A fixed setting suits an exhaust line that runs at one steady rate. Speed that must change through the day needs an external controller on the signal input instead. Mark the final position so the setting can be restored after service. With twenty pieces in a sales unit, one pack covers a row of fans across a facility. Check the setting whenever the fan or its filter is serviced.
Key Features
- 10 kOhm Element: Rotary potentiometer per the Ruck data sheet.
- 0-10V Speed Signal: Wiper voltage sets the EC fan speed.
- Terminal Box Mount: Connects inside the fan's own terminal box.
- Three-Lead Wiring: Ground, 0-10V signal and +10V supply.
- 50°C Ambient Rating: Rated for surroundings up to 122°F.
- 20-Piece Sales Unit: One pack covers many fans.
Technical Specifications
| Specification | Value |
|---|---|
| Brand | Ruck |
| Model | MTP 40 |
| Part number | 147359 |
| Type | Rotary potentiometer |
| Resistance | 10 kOhm |
| Output | 0-10V speed signal (wiper) |
| Supply | +10V from the fan electronics |
| Leads | 3: GND, 0-10V, +10V |
| Body diameter | 16 mm |
| Overall length | 115 mm |
| Max ambient temperature | 50°C (122°F) |
| Mounting | Inside the fan terminal box |
| Sales unit | 20 pieces |