AAON ASM08070 Motor Speed Controller
Specifications
- Product Name: Motor Speed Controller
- Voltage Options: 240 V, 480 V
- Control Method: Phase control method
- Motor Types: Permanent split capacitor (PSC) or shaded pole
- Speed Modes: Low and high speed
- Control Power Inputs: 24 VAC
PRODUCT NAME REVISION LOG
| REVISION AND DATE | CHANGE |
| Rev. C. November 4, 2025 | Updated part numbers |
| Rev. B, October 4, 2023 | Updated the logic power source in the 240V and 480V specification tables |
| Rev. A, September 16, 2021 | Original |
PRODUCT NAME PARTS REFERENCE
| PART DESCRIPTION | PART NUMBER |
| Motor Speed Controller (240 V) | ASM08070 |
| Motor Speed Controller (480 V) | ASM08077 |
| Motor Speed Controller (240 V) (2024 and previous) | ASM02907 |
| Motor Speed Controller (480 V) (2024 and previous) | ASM02908 |
OVERVIEW
General Information
Overview
- The Motor Speed Controller is designed to control the speed of alternating current (AC) induction motors in combustion air blowers.
- The Motor Speed Controller is used with blower motors with
- Hall effect tachometer sensors included to help facilitate blower speed control.
Features
There are two Motor Speed Controller options, the 240 V andthe 480 V. Both controllers function the same, but are equippedwith a different voltage power supply. See Figure 1, this page fordetails. The Motor Speed Controller controls speed based on thedip switch settings. The controller provides two speed modes,low and high speed. The two modes are controlled by 24 VAC control power inputs.
CAUTION: The controller uses a phase control method to adjust the voltage supplied to the motor. Confirm with the motor manufacturer that the motor being controlled is acceptable for this type of operation. Motor type must be permanent split capacitor (PSC) or shaded pole and be equipped with a one pulse per revolution Hall effect tachometer sensor.
Figure 1: Motor Speed Controller 240 V vs. 480 V
Dip Switch Settings
In Two Speed applications, the low speed is set by the sum of the rpm values for all switches that are in the open/off position. See Table 1, this page for dip switch settings.
| Dip Switch | RPM |
| 1 | 20 |
| 2 | 40 |
| 3 | 80 |
| 4 | 160 |
| 5 | 320 |
| 6 | 640 |
| 7 | 1280 |
| 8 | 2560 |
Table 1: Dip Switch Settings
NOTE: If the dip switch setting is outside of the 1000-3400 rpm range, it is invalid and the fan will run at 100%.
Dip Switch Settings
Dip Switch Calculation
To determine the motor speed, calculate the sum of the values for all switches in the open/off position. For example, if switches 1 ,3 ,5, and 7 are open/off, the motor speed is 1700. See Figure 1, this page for details.
Figure 2: Motor Speed Controller Dip Switch Settings
Motor Speed Controller Dimensions
Figure 3: Motor Speed Controller Dimensions
INSTALLATION AND WIRING
Wiring
See Tables 2 and 3, this page for the Motor Speed Controller 240 V and 480 V specifications.
| Motor Speed Controller 240 V | |
| Specification | Value |
| Logic Power Source | 18-30 VAC@3VA |
| Motor Power Source | 204-254 VAC |
| Power AC Frequency | 59-61 Hz |
| Motor Current Rating | 4 A |
| Motor Compatibility | Permanent Split Capacitor or Shaded Pole |
| Full Speed Startup Time | 15 seconds |
| Power Connections | 1/4” quick-connect tabs |
| Analog Input Connections | Terminal Block, 14 GA Max |
| Tach Sensor Connections | 3-pin 0.1” MTA Connector |
| Analog Control Range (2-10V) | 1000-3400 RPM |
| Storage Temperature | -40ºC to + 85 ºC |
| Operating Temperature | -40ºC to + 70 ºC |
| UL Classification | UL 60730-1,Automatic Electrical Controls |
Table 2: Motor Speed Controller 240 V Specifications
WARNING: Remove all power to the controller before making any connections or adjustments to avoid electrical shock or damage to the unit.
| Motor Speed Controller 480 V | |
| Specification | Value |
| Logic Power Source | 18-30 VAC@3VA |
| Motor Power Source | 408-528 VAC |
| Power AC Frequency | 59-61 Hz |
| Motor Current Rating | 4 A |
| Motor Compatibility | Permanent Split Capacitor or Shaded Pole |
| Full Speed Startup Time | 15 seconds |
| Power Connections | 1/4” quick-connect tabs |
| Analog Input Connections | Terminal Block, 14 GA Max |
| Tach Sensor Connections | 3-pin 0.1” MTA Connector |
| Analog Control Range (2-10V) | 1000-3400 RPM |
| Storage Temperature | -40ºC to + 85 ºC |
| Operating Temperature | -40ºC to + 70 ºC |
| UL Classification | UL 60730-1, Automatic Electrical Controls |
Table 3: Motor Speed Controller 480 V Specifications
Control Power
- There are three 1/4 inch quick-connect tabs for 24 VAC control power signal connections. The W1 terminal is 24 VAC common and ground.
- The W2 terminal is the high-speed input, and terminal W3 is the low speed input.
- If W2 is supplied with 24 VAC power and W3 is unpowered, the motor is will run at full speed.
- If W2 and W3 receive power, or if W3 receives power while W2 is unpowered, the motor speed will be controlled to the analog input voltage or the dip switch setting.
Line and Motor Connections
- The L1 and L2 quick-connect terminals should be connected to a 240 V or 480 V power supply. The M1 and M2 terminals should be connected to the motor.
Mounting
- The Motor Speed Controller has a factory-mounted aluminum base plate. The metal base plate helps the controller regulate temperature and facilitate proper heat dissipation.
Two Speed Wiring
- In Two Speed Mode, when 24 VAC power is applied only to terminal W2, the motor will operate at high speed.
- If 24 VAC power is applied to terminal W3 (instead of, or in addition to, terminal W2), the motor will operate at a speed determined by the dip switch setting. See Figure 4, this page for wiring details.
Figure 4: Two Speed Wiring
Inputs and Outputs
I/O Map
See Table 4, this page for Motor Speed Controller inputs and outputs.
| Motor Speed Controller | |
| Inputs | |
| W1 | Ground (for 24 VAC control voltage) |
| J1 | Fan tachometer feedback |
| L1 | Line voltage (240 VAC or 480 VAC) |
| L2 | Line voltage (240 VAC or 480 VAC) |
| Binary Inputs | |
| W2 | Fan high speed (24 VAC) |
| W3 | Fan low speed (24 VAC) |
| Analog Inputs | |
| TB1 | 2-10 VDC variable fan speed input |
| Outputs | |
| M1 | Fan motor |
| M2 | Fan motor |
Table 4: Inputs and Outputs
SEQUENCE OF OPERATIONS
Operation Modes
- Operation
- The Motor Speed Controller is used to control the speed of PSC or shaded-pole fan motors. The binary inputs are used to switch between High and Low Speed Modes. In High Speed Mode, the fan operates at 100%.
- In Low Speed Mode, the fan is controlled by the rpm setpoint determined by the dip switch setting. Fan speed is provided to the controller by a Hall effect tachometer in the motor. If the fan speed is above or below setpoint, the voltage supplied to the fan will be decreased or increased to maintain the fan speed setpoint.
- Off Mode
- In Off Mode, there is no W2 or W3 input and the fan output is de-energized.
- High Speed Mode
- In High Speed Mode, the W2 input is energized with 24 VAC power and the W3 input is de-energized. The fan runs at full speed. If the W2 and W3 inputs are both de-energized, the fan output will de-energize. If the W3 input is energized with 24 VAC power, the fan will switch to low speed.
- Low Speed Mode
- In Low Speed Mode, the fan will operate when the W3 input is energized or when the W2 and W3 inputs are energized with 24 VAC power.
- When the fan is powered on, it will run at high speed for 15 seconds before switching to low speed.
- The fan speed will be maintained at a speed determined by the dip switch settings.
- In Two Speed Mode, the fan rpms are labeled on the circuit board. The switch position should be set to OFF to add that position’s rpm value. For example, for 2560 rpm, positions 1-7 should be set to ON and position 8 should be set to OFF.
- If the W3 input is de-energized, the fan will switch to high speed operation.
- The fan output will de-energize if both W2 and W3 inputs are de-energized.
CONTACT INFORMATION
- AAON Controls Support: 866-918-1100
- Monday through Friday, 7:00 AM to 5:00 PM
- Central Standard Time
- Controls Support website:
- www.aaon.com/controlstechsupport
- AAON Factory Technical Support: 918-382-6450 techsupport@aaon.com
- NOTE: Before calling Technical Support, please have the model and serial number of the unit available.
- PARTS: For replacement parts, please contact your local AAON Representative.
- 2425 South Yukon Ave
- Tulsa, OK
- 74107-2728
- Ph: 918-583-2266
- Fax: 918-583-6094
- AAON P/N: G097900, Rev. C
- Printed in the USA
- Copyright November 2025
- All Rights Reserved
FAQs
Q: How do I confirm if my motor is compatible with the Motor Speed Controller?
A: Consult the motor manufacturer to verify if your motor is a permanent split capacitor (PSC) or shaded pole type with a Hall effect tachometer sensor.
Q: What should I do if the fan runs at 100% speed?
A: Check the dip switch settings and ensure they are within the valid RPM range of 1000-3400. Adjust as needed to set the desired speed.
Documents / Resources
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AAON ASM08070 Motor Speed Controller [pdf] Installation Guide ASM08070, ASM08070 Motor Speed Controller, Motor Speed Controller, Speed Controller |