Motor Controls Challenge

[tmitchell]

I"m a student learning motor controls and created a challenge for myself but am stuck. Here is the challenge:

Challenge 1
A) Using a blower (compressed air) set to a min level so that it would keep the light bulb from turning on. No air or falls below the min level, and fail the light comes on.


Challenge 2)

B) Using a blower for 10 seconds followed by a vacuum for 10 sec then alternating back and forth to again keep the light bulb from coming on. Think check engine light dont want to see that light come on.

At any point if there is no air or suction the light would be set on a 5 second delay before coming on. Same would be applied if the air or suction is not strong enough. Not worried in this example about to strong just if it generates enough or hits the min. In other words it has to hit a min or the light would come on, but nothing would be setup for max.


Here is how I thought I could accomplish this.

1) Using plastic tubing connected to a shop vac that could provided compressed air or suction.
2) This would then enter a 3 way control valve / pneumatic solenoid. This is hooked up to a toggle switch that would move it from normally open to normally closed for challenge #2.
3) From there it would travel to a pressure switch that could set the min amount of pressure or suction to remain open.
4) If not any it closes then the delay relay would be activated, and after 5 seconds would turn the light bulb on.

Challenge 2 would move the toggle switch from only the blower to both blower and vacuum with the delay relay connected that would be set to alternate.


I know lots of things to change to make this work, so give me your thoughts as I learn more about motor controls.

Who can solve this?

 

[SheffSimon]

Challenge 1, what's the light bulb got to do with anything? Does it just indicate low pressure? Seems like the challenge is to control air pressure with a fan, in which case connect a pressure transmitter into the motor controller, and use a PID function in the motor controller to control the motor speed to maintain the pressure. Program an output from the motor controller to switch on the lamp if the measured pressure is less than a low limit.

Is that challenge 2 also?

Have a think about the amount of energy your system would consume, also read up on PID control, it's a very very common control algorithm to maintain a process parameter to a desired setpoint, pressure, temperature, flow are typical process parameters.

I could also have used a pressure regulating valve to achieve a set pressure.

Last bit of info, lots of pneumatic solenoid valves are pilot operated, meaning the solenoid operates a small valve spool, to use the main air pressure to push the main valve spool. So if you have a vacuum on the valve incoming line, it won't work. You can get valves which are directly operated by the solenoid.

I don't really understand what you have written in your solution to be honest.

 

[tmitchell]

Challenge 1, what's the light bulb got to do with anything? Does it just indicate low pressure? Seems like the challenge is to control air pressure with a fan, in which case connect a pressure transmitter into the motor controller, and use a PID function in the motor controller to control the motor speed to maintain the pressure. Program an output from the motor controller to switch on the lamp if the measured pressure is less than a low limit.

Is that challenge 2 also?

Have a think about the amount of energy your system would consume, also read up on PID control, it's a very very common control algorithm to maintain a process parameter to a desired setpoint, pressure, temperature, flow are typical process parameters.

I could also have used a pressure regulating valve to achieve a set pressure.

Last bit of info, lots of pneumatic solenoid valves are pilot operated, meaning the solenoid operates a small valve spool, to use the main air pressure to push the main valve spool. So if you have a vacuum on the valve incoming line, it won't work. You can get valves which are directly operated by the solenoid.

I don't really understand what you have written in your solution to be honest.

Thanks for the reply. Alright here is more on my solution:

Challenge 1:

Air is blown from the air compressor to the solenoid valve where it would be set as normally closed. Light should remain off. From there air would travel to the pressure sensing switch which would be set to normally closed. If enough air is supplied at the pressure switch the light would remain off. If no air or not enough air is supplied the relay will wait 5 seconds before turning the light on, which is a fail.

Challenge 2:
A toggle switch is moved that will reverse the process after 10 seconds and then alternate. So in this case I was thinking that the relay or maybe its the solenoid (not sure) could be set to alternate between suction and blown air. So for the first 10 seconds its really the same as challenge one, but in the this challenge after 10 seconds it switches to suction. So using the 5 second delay would switch the shop vac from blowing to vacuum mode. Again the goal is to keep the light from coming on.

So for the compressed air coming is the pressure valve would use the high pressure and for the suction would use the low pressure part.

So can the toggle switch do this and if so do i wire it into the relay or the solenoid?

 

[alexanderzingman]

Great solution ... first i try to do it my self but not able to complete thanks for sharing your solution