Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.





We have a problem with a AMOT VALVE ACTUATOR, we cannot to put the lever flicks in the auto position. In the AMOT VALVE has three leds operation ( healthy,warming and fault) the all leds are flashing in 2hz, in accord of manual this indicate two possibilities : First is waiting a calibrate procedure and the other factory setup mode.
The actuator is controlled by EXTERNAL PLC ( 4 a 20 ma), it your function is open or close the amot valve for to cool the generator motor, controlling the engine temperature.

Then, we follow all manual instructions, however, we did not sucess. If anybody can help us about this problem, we get very happy.

Best regards,

Carlos Ney
Electronic technician QGOG


What powers the actuator to make it move? Electricity or air?
Is it an electric or pneumatic actuator?

Find the manufacturer identification tags and provide the brand and model number(s)
Actuators and positioners are frequently from different vendors.


The actuator is moved electrically. The actuator voltage is 120 vac , but who's defines the position of the actuator is the sinal 4 a 20 ma, wich comes from de external PLC.


In the absence of any particular model ID . . . .

Most electric actuators operate in roughly the same way. The 4-20mA demand/control signal 'position' is compared to the current motor shaft position (physical slidewire or non-contact electronic equivalent). If the control signal 'position' is different than the actual motor shaft position, then one of two motor coils is energized. One coil drives the motor Clockwise (CW), the other coil drives the motor Counter Clockwise (CCW). The coil is energized and the motor rotates until the motor shaft position is the same as the position represented by the control signal. Limit switches open the motor coil circuits when the motor is at its operating limit.

Possible failures. Sometimes the slidewire or position sensor fails. Sometimes a limit switch fails open. Sometimes a thermal cut-out switch, in series with the motor coil common opens or fails open. Sometimes the 4-20mA card fails. Some actuators will mechanically 'jam' if the travel has moved into the mechanical limit stop. Jams usually have to be fixed mechanically (a stop bolt loosened and a stop bolt backed off) to free the shaft (the limit switches and mechanical stops should be re-calibrated). Momentarily applying motor coil voltage to the wiring terminal of one of the coils should drive/jog the motor in the expected direction and prove the motor coil integrity. When you find a manual and a schematic for that actuator you should be able to figure out what's failed.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close