DC Motor Forward reverse controllred by limit switch or proximity sensor

[akocmrsuave]

Motor specs:
DC Brush motor
Motor torque- 0.4-0.5Nm
Rpm - at least 4000 rpm
stall torque- greater than 0.5Nm

parts needed:
contactor
relay
sensor
power supply

Anyone Can you help me because I need to source for parts to design a test equipment, I need a simple set up, to drive a dc motor to move forward and reverse it would be driving a shaft when it reach a limit switch or sensor it will be automatically switch the motor in reverse, when it reached another limit switch on the other end it will move in forward motion. The movement will continue its forward reverse until I press the stop button. i need a circuit or ladder diagram for the connections, and maybe some suggestion to which parts i can buy.

 

[alec_t]

Switching instantaneously from forward to reverse may cause electrical and/or mechanical problems. Wouldn't you need a stop-pause-reverse sequence?

 

[Reloadron]

I strongly agree with Alec. You mention:

Motor specs:
DC Brush motor
Motor torque- 0.4-0.5Nm
Rpm - at least 4000 rpm
stall torque- greater than 0.5Nm

When you say driving a shaft do you mean a lead screw or ball screw configuration? I can't get past the 4,000 RPM plus so thinking the motor is geared down? You really need to provide much more info about the motor and answer alec's question.

Ron

 

[mbarazeen]

Check the attached, it may work for your need..

 

[Joe G]

(alec t) "Switching instantaneously from forward to reverse may cause electrical and/or mechanical problems" ....... i made a quick pcp shaker with a 6v motor and a dpdt switch.
it worked for about 4 minutes and then the magic smoke came out of the switch first.

 

[mbarazeen]

(alec t) "Switching instantaneously from forward to reverse may cause electrical and/or mechanical problems" ....... i made a quick pcp shaker with a 6v motor and a dpdt switch.
it worked for about 4 minutes and then the magic smoke came out of the switch first.

A time delay relay can be replaced to do the job. for semiconductor application 555 can be used or a simple RC delay can be used to give a delayed start in both directions.

 

[akocmrsuave]

Hi thanks for the advice if i would connect a dpdt time delay is this correct? see the jpeg image i attachedView attachment 62461

BTW i am going to use the DC motor JRS-977PM-4048 24dc

 

[alec_t]

Something like this, perhaps? Needs a N.O. limit switch at each end of the travel. When a limit switch closes, (1) power to the motor is cut off for ~1 sec and (2) a latch is set or reset. The latch drives a relay with DPCO contacts to reverse the motor direction.

 

[colin55]

You can do it much more simply by delaying the limit switch via a transistor and electrolytic so the relay does not activate for say 1 second.

 

[alec_t]

Simpler would be better, but I can't see how that works for both ends of the travel. Can you provide a schematic to clarify things Colin?

 

[crosslakeguy]

garage door openers do this at a small load...... the start contactor takes a serious pounding, may have something to do with the residual induced current? not an engineer, just a guess. It will reverse at minimal load. but will not stand the test of time.. depending on the torque requirements, a servo motor or a stepper motor will last if you want a bullet proof system.