Reverse a DC motor at a set current - UK Vintage Radio Repair and Restoration Discussion Forum

qtronix · 3rd Feb 2022, 7:05 pm

sorry if this is not allowed, but there are a lot of knowledgeable people on here.

i have got a paper shredder that i want to use for a project for expanding cardboard like this.

https://www.instructables.com/Cardbo...-Paper-Shredd/

the one i have is a big beast. is there an off the shelf circuit or controller for auto reverse current sense.
there are so many sensors on this thing i am not even going to try and mess about with them.
adam

qtronix · 4th Feb 2022, 10:02 am

found this on the bay, going to order one see what it can do. i could wire up the over current relay to reverse the motor. found out the board is 0-5amp over protection. so will have to mod it. just dont no about the start up current wil do.

https://www.ebay.co.uk/itm/284578420....c100667.m2042

GMB · 4th Feb 2022, 10:33 am

I think I can say that most people are not familiar with this machine at all.

I would just comment that your thread talks of reversing a DC motor and yet it looks like an induction motor to me - going by the photos.

Terry_VK5TM · 4th Feb 2022, 11:55 am

We need pictures of the actual motor and if it is what I think it is , then that ebay module is not going to do the job.

One of your pic's shows a high voltage motor cap so I suspect the motor is 230V AC and already reversible using a switch.

Radio Wrangler · 4th Feb 2022, 1:11 pm

If that is the rating label on the motor, then it says it is a 50Hz motor, whichis not DC.

Also, the white component is a typical motor-run capacitor used with single-phase AC induction motors.

To reverse a single phase induction motor, you first need a special motor with both ends of the start winding accessible separately from the main winding. You need a phase reversing switch for the start winding. You need a sequencer too stop the motor,let it come to rest (important!) reverse the phase of the start winding, and then restart the motor. If you don't let it come to rest, it'll start back up in the same direction as before.

David

qtronix · 4th Feb 2022, 8:11 pm

quick test. still have to finish making the box. might just leave it with an on and off switch.

https://www.youtube.com/watch?v=Z-hch5MIbUs

3rd Feb 2022, 7:05 pm	#1
qtronix Pentode Join Date: Dec 2021 Location: Willenhall, West Midlands, UK. Posts: 161	Reverse a DC motor at a set current sorry if this is not allowed, but there are a lot of knowledgeable people on here. i have got a paper shredder that i want to use for a project for expanding cardboard like this. https://www.instructables.com/Cardbo...-Paper-Shredd/ the one i have is a big beast. is there an off the shelf circuit or controller for auto reverse current sense. there are so many sensors on this thing i am not even going to try and mess about with them. adam Attached Thumbnails

4th Feb 2022, 10:02 am	#2
qtronix Pentode Join Date: Dec 2021 Location: Willenhall, West Midlands, UK. Posts: 161	Re: Reverse a DC motor at a set current found this on the bay, going to order one see what it can do. i could wire up the over current relay to reverse the motor. found out the board is 0-5amp over protection. so will have to mod it. just dont no about the start up current wil do. https://www.ebay.co.uk/itm/284578420....c100667.m2042

4th Feb 2022, 10:33 am	#3
GMB Dekatron Join Date: Aug 2003 Location: near Reading (and sometimes Torquay) Posts: 3,095	Re: Reverse a DC motor at a set current I think I can say that most people are not familiar with this machine at all. I would just comment that your thread talks of reversing a DC motor and yet it looks like an induction motor to me - going by the photos.

4th Feb 2022, 11:55 am	#4
Terry_VK5TM Nonode Join Date: Oct 2010 Location: Tintinara, South Australia, Australia Posts: 2,340	Re: Reverse a DC motor at a set current We need pictures of the actual motor and if it is what I think it is , then that ebay module is not going to do the job. One of your pic's shows a high voltage motor cap so I suspect the motor is 230V AC and already reversible using a switch. __________________ Terry VK5TM https://www.vk5tm.com/

4th Feb 2022, 1:11 pm	#5
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,876	Re: Reverse a DC motor at a set current If that is the rating label on the motor, then it says it is a 50Hz motor, whichis not DC. Also, the white component is a typical motor-run capacitor used with single-phase AC induction motors. To reverse a single phase induction motor, you first need a special motor with both ends of the start winding accessible separately from the main winding. You need a phase reversing switch for the start winding. You need a sequencer too stop the motor,let it come to rest (important!) reverse the phase of the start winding, and then restart the motor. If you don't let it come to rest, it'll start back up in the same direction as before. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

4th Feb 2022, 8:11 pm	#6
qtronix Pentode Join Date: Dec 2021 Location: Willenhall, West Midlands, UK. Posts: 161	Re: Reverse a DC motor at a set current quick test. still have to finish making the box. might just leave it with an on and off switch. https://www.youtube.com/watch?v=Z-hch5MIbUs