How to easily switch rotation direction on a DC electric motor

[@Xynudu]

NOTE: To prevent arcing damage in the switch when using high DC voltage ALWAYS switch off the inverter/power supply OR reduce voltage/speed significantly before changing direction with the toggle switch. You should NEVER change motor direction at speed. A small correction - the terminals opposite the toggle direction connect to the centre power supply feed. Cheers Rob

[@justsheeeps134]

So what if we used a motor controller and changing it does it will damage the motor ?

[@AztecWarrior69_69]

Actually that switch is not rated for DC current. Most of the time if it says 15 amps at 120 v AC it translates to around 10 amps DC at 24v and 6 amps at 12v. The contacts on DC switches are generally larger and made of different material that can handle the arcing. I think it's mostly brass. Brass doesn't spark or arc well. That's why they use it for regulators and fittings in anything that has explosive gasses. If they sold you that switch claiming it is for DC then you need to be very cautious

[@garyhardman8369]

Brilliant video Rob. Very clearly explained for those who may not have an electrical background. I just have to mention that a switch rated at 15A AC, does not have the same rating for DC. AC current takes the form of a sine wave, at a frequency of 50 HZ (lets assume we are in the UK, some other countries use 60 HZ). So, the current rises from zero to it's peak positive value and back to zero in 1/100th of a second. Then, the current rises from zero to it's peak negative value and back to zero in the next 1/100th of a second. Therefore, every 1/100th of a second, the current in a mains AC circuit is zero. When you turn off a switch, the tendency is for the current to draw an arc across it's contacts. If the current is AC, then the maximum time that the arc can survive is 1/100th of a second, then as the current passes the zero point, it has to go out. In a DC circuit, the current never goes to zero, so the contacts can, and sometimes do keep on arcing. This obviously depends on the contact separation and the speed that the contacts open. I used to work in the design and testing of very large DC systems. Specifying and obtaining switches, contactors etc had to be carefully considered. I'm not trying to be a 'smartass' here, just don't expect a 15A AC rated switch to last very long on 15A DC.

[@Xynudu]

Thanks Gary, I understand what you say. That's why I would always reduce speed (voltage) before direction change (as shown) to reduce arcing in the switch. I should have pointed that out. I did a DC conversion on my Chinese metal lathe quite a while back and wired it up so the original stop button shut off the AC to the inverter. Then switched at the toggle, the same routine as before (with the previous AC direction change drum switch). This prevented any arcing issues. Feedback will still occur, but the inverter seemed to be able to handle it (probably incorporated in the design as it's got to deal with this on most DC motor applications). Plus you should never switch motor direction when it's at speed. Thanks for the heads up advice to viewers/readers of the implications with DC. I eventually converted the lathe back to AC as heat rise problems with DC just made the whole exercise a negative experience, with the only advantage being to get cheap variable speed control (which really isn't all it's cracked up to be, from a machining perspective). I have now pinned a note at the head of the comments section warning of this issue. Cheers Rob

[@garyhardman8369]

Hi again Rob. Interesting to hear about your lathe power conversion. I have an early 1950's 'EW Stringer' lathe, which was manufactured in England. I bought it from a chap on Ebay, several years ago. It came to me with what looks to be the original 1/2 horse single phase induction motor. Speed control was limited to three stepped pulleys, and of course no reverse. In a stroke of luck, I managed to find a small three phase motor, complete with single to three phase variable speed drive for about £130.00. (Ebay again) Fitting this kit to my old lathe has made it much more useful. I bought that particular lathe because it needed to fit in my attic workshop. There is a good article online, which tells the story of the 'EW'. I have attached a link, if you were curious to see: www.lathes.co.uk/ew/ Cheers, Gary.

[@Xynudu]

Hi Gary, Some of the old small lathes are really nice. That one looks good. Too many people get hung up on lathe size and really miss the point as far as a usability is concerned. Plus you can generally get these small old lathes for a song these days, so why not have several machines and set one up just for collet work. It's not a big outlay. Wear can be an issue, but generally if you buy wisely you can avoid that side of things, or minimize it. Be good to see a video run around of it. I have three lathes as you may have seen. Max size is 10" swing Chinese, 9" swing tool makers , and Sherline micro lathe. All handy. The whole lot cost me less than $2K AU all up in restored operating condition. Just shows you don't have to spend a fortune to set up a workshop for metal work. Cheers Rob

[@JB-ym2yy]

Very nicely done and easy to follow. Now I can fix the grand daughters mini pottery wheel which is spinning in the wrong direction for right handed people. Your diagram is perfect for following the process.

[@Xynudu]

Glad it helped!

[@GlenB1963]

A very easily understandable video. It was doing my head in. Thank you so much. ❤

[@Xynudu]

You are so welcome!

[@derekwilkinson7939]

I didn’t know you do that, like you say it’s simple but if you don’t know you don’t know. Great video well explained.

[@pburbury]

Very well explained in simple language BRILLIANT

[@Xynudu]

Thanks a lot. Cheers Rob

[@SteamEngines-Jim]

Thanks for the drawing, I'm not electrically minded whatsoever but I should be able to follow that because of your explanation Rob.

[@lukes6868]

Thank you, Also the diagram helped heaps. Nice and clear instructions, both audio and diagram.

[@Xynudu]

You're welcome!

[@mikekrening7327]

Hi Rob, thanks for the explanation. Wiring is not my strongest suit. I always find a way to figure it out but the more tips the better. Thanks

[@SteveJordan]

Hi Rob, That's excellent. I've been wondering how this can be done for years!

[@Amoux11]

this was supper helpful thank you!!!

[@Xynudu]

Thanks for the feedback.

[@pgs8597]

G’day Rob, well explained. Good thing you noted it was a double pole switch. Cheers Peter

[@Xynudu]

Hi Peter, Yes, it was stating the bleeding obvious, but even showing the switch model number isn't enough at times ;) I don't expect this video will interest a lot of people, but it's something not covered by many bases. Handy for anyone playing around with DC and old treadmill motors. A path well worn by me. Cheers Rob

[@AmateurRedneckWorkshop]

Every one loves DC motors for the easy direction and speed control. The fly in the ointment is that you have to buy a power supply.

[@Xynudu]

Hi Harold, Yes, and those power supplies don't come cheap, even secondhand. I imported a box of KBIC's from the USA years back and sold most of them to associates. Finished up they paid for the two I have left for personal use. So I depleted the available USA stocks quite a bit. He He. Bloody Aussies ;) I see Banggod have a few cheapish AC - DC power supplies. I might check them out. Cheers Rob

[@AztecWarrior69_69]

That's not true. There are thousand of appliances out there that have DC power supplies. You just have to know where to look.

[@pappyweasel7766]

@@AztecWarrior69_69 do tell! Please 🙏 and thank you!

[@ChrisB257]

Center off switch is super useful for that job.

[@RetroSteamTech]

Hi Rob. Been doing this for years but then for my sins i was an electronics engineer! It might be worth pointing out that on most toggle switches like the one you used the opposite terminals are the the ones that short when the switch is made. For example when you flick the switch to the left it's the 2 right-hand terminals that connect. My old apprentice master would say that the toggle points to the terminals that are connected 🙂

[@Xynudu]

Hi Alan, That's interesting. I agree, it's something I hadn't thought of, and didn't bother to check the relationship on the back. I expect it's just as you say. I've only ever wired it up and it worked. Didn't think about the internals too much :) I made an assumption and am almost certainly wrong. Thanks for the heads up. Cheers Rob

[@Xynudu]

Hi Alan, I checked the pole throw/terminal relationship this morning and you are dead right. They are opposite orientation. Slaps head. Wrong again :) Cheers Rob

[@RetroSteamTech]

@@Xynudu Hi Rob, for the way the switch is wired here it doesn't actually matter. It's only really worth noting if you are mounting a switch in a panel and it's the on-off type. Some of them have a slot cut in the threaded portion to take a washer with a tag on it to stop the switch from rotating. The outer part of the washer has another tag that locates in an indent in the panel. Obviously if you use this the switch can only go in the panel one way. Cheers, Alan.

[@howarddavis3294]

Very good video, thanks.

[@Xynudu]

Glad you liked it!

[@marty3553]

Absolutely brilliant video, thank you so much , now I understand ❤

[@Xynudu]

Thanks for the positives. Cheers Rob

[@madeingreatbritainchannel]

Hi Loved the video, what was the link for the project kit from banggood?

[@Xynudu]

The kit shown is no longer sold. However, BG do sell the individual components if you search their site eg.: "No Power Spindle Assembly Small Lathe Accessories". Cheers Rob

[@mr.russerzplace...1448]

I've Been wondering how the hell that worked . Then I picked up a winch for me atv but it had no controller so I had to abort the whole idea I had to build my own working universal machine. Cool thanks much !!

[@fatgressor]

Awesome explanation thanks !!!

[@RickRose]

Brilliant explanation. Thanks Rob!

[@gregoryrobertson4733]

Great job buddy. Thanks

[@Xynudu]

You're welcome.

[@DavidTerceira-ss2yh]

Thank you, helped me tremendously!!😂

[@Xynudu]

You're welcome!

[@hendrikriedstra7857]

Would that system work on a 240 volt Wood turning lathe? It looks simple enough but I'd like to be sure.

[@erfut]

Thank You.

[@Xynudu]

You're welcome

[@daveandersonangry]

thanks for the info very helpfull

[@7559kenny1]

the video is what I was looking for BUT can't see the wires from the circuit board to the switch so no joy for me I got to turn one way, a better view of the switch and wiring including the circuit board I probably could work it out

[@RobertSzasz]

Hmm, I think I would connect the motor to the middle set of terminals and cross over the power for the outer set of contacts because it's a bit easier to understand at a glance. But I guess this leaves fewer bits of metal energized when off.

[@makeitathome1327]

Im building a electric bike, and i have a question about the rotation of the motor. I've built my diy bike, but the motors spinning the wrong direction. How can I reverse the direction of the motor? I have it hooked up to a 2 pin rocker switch and a 22.2v 1400mah battery and it all works, but how would i have to change it if i wanted to make it go the opposite direction? Its going clockwise now, but i want it to go counter clockwise. If i swap the connectors on the motor ( like connect positive motor wire to negative battery wire and negative motor wire to positive battery wire ), would that work?

[@Xynudu]

That works with all the DC motors I've used. Try it and see. It can't do any harm. Cheers Rob

[@makeitathome1327]

@@Xynudu Ok thanks! Im going to test it right now hopefully nothing blows up or anything

[@Xynudu]

You may find it will have slightly more power in one rotation direction than the other. That's because they usually set the magnetic field timing for best effect in one direction. It should run the oher way without issue and in practice you will barely notice it. Good luck. Cheers Rob

[@vault1230]

Awesome, does this work with AC as well?

[@Xynudu]

No.

[@34k5]

Now how would this work for a reversible 120v motor? I have a drum switch and it makes sense to me but could it be done this way?

[@Xynudu]

This only works with DC motors.

[@MabrayFarm]

It will work with a split phase ac motor, you would be doing the same thing with the drum switch. You just have to make sure you reverse the start winding circuit and then you can control which direction the motor will start.

[@dcw56]

Thank you. i always seem to have trouble with this! I appreciate it! Oh! What is this kind of switch called , by name, please. Much appreciation mate! Dean

[@Xynudu]

DPDT 6A 240VAC Heavy Duty Centre Off Standard Toggle Switch.

[@paulk3573]

Hello sir, I am always very appreciative of all the themes that you address. Concerning the reversal of the direction of rotation of the motor, would you have a link to acquire 1 switch on / off / on at a deceptive price. Another question, when you vary the speed, does your device conserve torque? Hoping for an answer, I greet you courteously. P. K. (French)

[@Xynudu]

Hi Paul, the torque will change with the speed, as the voltage is varied. Less voltage means less torque. That switch is readily/cheaply available from most electrical hobbyist stores that sell components and from Ebay. You want a DPDT 6A 240VAC Heavy Duty Centre Off Standard Toggle Switch (about 3 Euro). Cheers Rob

[@paulk3573]

Hello sir, Many thanks for your quick and positive response. I searched on Ebay with your precise indications and of course I saw a switch on off on at ~ 3 €, so it is perfect and significantly less expensive than those I had seen. Thank you again, I very much appreciate your seriousness and your availability. P. K. (French)

[@Zeronial01]

Hello sir can you help me, I need a motor that can slowly move a miniature door from side to side but I also need something that can stop the motor when the door reaches the far left and right ends so it doesn't cause damage to the motor. Do you know where I can find such parts? P.s, is there anything that can move the door inward and outward from the frame?

[@Xynudu]

A window supplier should be able to answer your question, There are almost certainly kits available to do this, particularly for high level hopper windows.

[@Zeronial01]

@@Xynudu Thanks, I'll try asking but I'm not sure if they'll help since the door is only 3 in and shaped like a gear.

[@Xynudu]

If the door is that small they won't be able to help. Unless you say the size up front, I'm just wasting my time replying. LOL. For something that small you will have to fabricate some sort of drive system. Maybe a hobby shop can advise on this. Probably a worm drive would work. To stop the drive just use a simple reed switch at each end of the movement to cut the power.

[@Zeronial01]

@@Xynudu I apologize, I didn't mean to withhold that information. I was under the impression that the motor featured in the video wouldn't be able to handle a normal sized door without overheating and/or burning out, hence the assumption. However, yes it's a gear shaped door made to replicate a vault door from the Fallout games as part of a miniature diorama, hence the need to find the right equipment to move the door. I'll check to see if my town has a Hobby shop and look into a worm drive and reed switch. Thanks for helping.

[@bricago2302]

@zeronial01 I’m working on a similar project to yours. If you come up with a way to get your vault door operating, please update here. Thank you.

[@colinwarner7762]

Rob, cant find this switch anywhere, any ides please. Colin uk.

[@Xynudu]

Hi Colin, Any electronics hobby/component shop like Jaycar will have it, also on Ebay. Just quote/search the number and specs shown on the side of the switch in the close up shot. Cheers Rob

[@colinwarner7762]

@@Xynudu Thank for your quick reply Rob, I will try harder. regards Colin.

[@Xynudu]

I see BG have them but currently sold out. Dirt cheap. www.banggood.com/20A-125V-On-Off-On-Double-Pole-Toggle-Switch-Double-Throw-DPDT-Heavy-Duty-p-992569.html?cur_warehouse=CN You can also use two poles on one of these: www.banggood.com/Voltage-Toggle-Type-A-Switch-For-Grade-9-Pole-25A-250VAC-KN302-120240VAC-ONOFF-p-1425771.html?rmmds=buy&cur_warehouse=CN Cheers Rob

[@AndresHerrera-gx3er]

good afternoon brother I am fine, but I have a doubt I bought a 3v motor and if I put a 3.8v cell battery it will burn it?

[@Xynudu]

Hi Andres, Hard to say. The percentage over voltage increase is 27% so that may be OK, but run time may have to be reduced. I don't expect it will burn out from the voltage, but heat build up could be a problem. It's a suck it and see situation. Cheers Rob

[@AndresHerrera-gx3er]

@@Xynudu ty bro, I will make vents :)

[@Xynudu]

Hi Andres, It might be OK. Just monitor the temperature first. If it warms up more than you think is good. then add a few vents. Cheers Rob

[@allengentz7572]

Yes Rob Simplesness rules supreme !

[@iiinicky6224]

Thanks!

[@Xynudu]

No problem!

[@jessestrum]

thanks robbie

[@jonknight9048]

Would you have a link for the inverter please?

[@Xynudu]

Hi Jon, Which inverter do you mean ? The KB or the Banggood one ? Cheers Rob

[@jonknight9048]

@@Xynudu I will eventually be using a treadmill motor so whichever would be best for that . It would be replacing a mc60 board from memory

[@Xynudu]

OK. KB Electronics make several which are suitable for treadmill motors. These are a commercial grade inverter with provision for a potentiometer as shown in the video. This is a link to the current KBIC range: acim.nidec.com/drives/kbelectronics/products/variable-speed-dc-drives Here is a link to the older units which you can get off of Ebay (used) and do the job fine: www.kbelectronics.com/data_sheets/kbic.pdf These come in a range of flavours and will do up to 180 volts and three HP, when fitted with the correct resistor module for the motor HP (interchangeable). I used a 90 volt unit in the video, but also have a 180 volt unit for larger treadmill motors. The electrical ratings at top of page 11 are what you should be examining to select the KBIC model which is correct for your AC supply and the voltage of the donor DC motor. So be sure to get the correct model. Cheers Rob

Nice one.

[@Swagnermite]

Genius!

[@pierresgarage2687]

Can't be much simpler...!!! ;)

[@martinb554]

Thanks

[@Xynudu]

You're welcome.

[@cigarcaptain]

perfect night for this

[@AztecWarrior69_69]

That 15 amp switch can handle the load of a treadmill motor however you don't seem to realized that you are taking that 15amps AC is the reason it can take it. 15 amps AC is only like 6 AMPS DC. that switch is designed for AC.

[@johanandersson9287]

C'mon Rob - spill out what the project really is! Cheers, DIYSwede

[@Xynudu]

I'm thinkin, I'm thinkin !!!!!

[@johanandersson9287]

@@Xynudu -Awww - just a high-torque motor for your Sherline, perhaps? Cheers, DIYSwede

[@Xynudu]

I actually did look at/compare it with the Sherline motor size wise, but there's no way I would ever change the original format - that would be scandalous. Cheers Rob

[@AztecWarrior69_69]

Did you know that here is an even easier way to wire a polarity control switch? Use a vehicle power window 5 pin switch.

[@Xynudu]

That's a new one on me. I can see how that would work, but how would it handle the amps ?

[@AztecWarrior69_69]

@@Xynudu They are meant to direct connect to DC current from a car battery to run the window motor, so they meant to handle it.

[@3613jeremy]

This stuff is what annoys me about a bunch of these KZbin DIY videos they make stuff sound so complicated when videos like this show the basic and simple answer I guess those 20min videos pay better

[@gus6rocks]

I know it's a test setup, and a good explanation, but those shitty crappy crimp connectors are most amateurish.

[@Xynudu]

Yes they are crappy and not recommended. I only used those because it was fast and not important - it's just a demonstration. All those leads will be scrapped later. If that's all you have, always run solder in from the connector spade end to make sure they stay connected. Cheers Rob

[@andyZ3500s]

@@Xynudu there is always one out there. He wants you to solder all those connections then undo them for a quick demonstration. Well done video thanks.

[@905Speed]

this is over explained....