[This thread refers to https://forum.allaboutcircuits.com/threads/40-volt-3-wire-brushless-lawnmower-motor.181392/ from where it was moved. —Moderator]

Hi !! Was doing a deep dive in search for some 40 volt idea's and few questions I had on the wiring of such. This thread/post caught my attention and interested me!

I got a bunch of 40 volt Ryobi push mowers that I didn't really want, but thought "Gee what could I do with these other than a mower!?" The reason they were given up on....is Ryobi had an era where the controllers went bad from the get-go, and of course they are not able to be replaced.

So my thought is, let's make other things out of the motor. I'll steal the plastic battery holder that is basically positive and negative wire with I think a smaller wire that is a safety if things get too warm? or some say it's for the led light at least on power tools? So not sure on that small wire at the battery hook up port.

The next thing I wanted to steal is the motor that turns the blade, but in my case, I want it to turn other things made into projects. One is a pump. I'm sure U seen those hose hook up pumps that U throw in your drill and wam! ya got a pump to empty the outdoor fish pond or such.

If my eye's saw right there's like 3 wires coming out of that motor. Right away my mind went to where I've seen AC motors in hot air systems and the reason there is= each wire is a different speed. I think I saw the same on the kids scooter that I was able to find a controller and replace for him so I did not study that set up.

so?? I took a look online to just find a basic controller for this project. found one for like 15bucks. It's a simple kind, it is made up of the control board and has an external speed dial or dimmer if U will, a dial like one through 5. and on off switch with two wires coming out to go to the motor.

I'm thinking ok..that's fine, but that's two wires when the motor has 3 wires or some have more. What would interest me to find a site that explains these motors with more than two wires coming out. I think the kids scooter has like 4 but I'm more interested in finding a diagram that explains the motor in the 40 volt Ryobi. I got to thinking also that one of those such wires to the motor may be a safety of sorts? So just ignore that certain wire of color?

I did see a video where a guy learned that his controller had a "tilt" feature in it. He made the mistake of mounting it sideways and nothing would work. I however as said, will not be using the controller with these motors because they are messed up=junk.

So? anyone with any idea's on finding a blueprint on what the wires do on these motors? and/or an idea that I should buy a different kind of controller other than the basic one beings sold on Amazon?

 

Thank you for moving this to it's own Thread...post. No, I was not trying to "hijack" someone else's thread or post. I actually thought it was a great post with many idea's. However it switched over to the controller topic and I couldn't find the actual answer to the question of the wires in the motor.

I find it amazing that there's not a U tube video of someone just taking the motor wires and "hot wire" them to just run a check that the motor is fine without the controller... or have a basic controller to hook up to make sure the motor is fine and that the controller is faulty and then go spend the big bucks of 60$ or more for the OEM controller made for that unit.

anyhow, I'd be tickled pink to see myself or folks be able to hook a simplified controller to a motor and make it into an invention thing of sorts... I just noticed that ebay has simple ones at 7$ compared to 15 at Amazon...

I again thank the Moderator for moving this and hope that some will share their thoughts or idea's. Meanwhile I'm going back to the internet to see if I can find some clues.

 

If the battery powered motor with three wires is a brushless DC motor that needs an external driver module, all that you can get with "hot wiring" will be heat, as it burns out. There are other drivers available for BLDC motors, and some of them do not require position sensors inside the motor. That is the kind you will need. They should be a better choice than the OEM driver, which I think was the source of the problem. And also cost less.

 

I have a 3-wire DC motor that looks like this. One wire (green/yellow) is CHASSIS. The other two (blue and brown) is DC power. The other set of three wires is a tachometer output.

 

. What would interest me to find a site that explains these motors with more than two wires coming out.

You will find some explanation here. https://howtomechatronics.com/how-it-works/how-brushless-motor-and-esc-work/
There are two types of commutation for what is essentially the same motor, BLDC and 3ph ECM motors.
The difference is in the way they are commutated.
The BLDC has only two windings energized at the same time whereas the 3ph version has all three powered.
You need a suitable controller, although some versions have the controller built in, as is often seen in HVAC motors.

 

I have a 3-wire DC motor that looks like this. One wire (green/yellow) is CHASSIS. The other two (blue and brown) is DC power. The other set of three wires is a tachometer output.

View attachment 308145

The brushes on that motor are rather obvious.

 

If the battery powered motor with three wires is a brushless DC motor that needs an external driver module, all that you can get with "hot wiring" will be heat, as it burns out. There are other drivers available for BLDC motors, and some of them do not require position sensors inside the motor. That is the kind you will need. They should be a better choice than the OEM driver, which I think was the source of the problem. And also cost less.

Yes, as I've been doing research it does seem this is a BLDC motor and my thought was that the controller is needed to properly run or test such... this convo got started cuz I was impressed with the cheap controllers but they are two wire to the motor and that makes me a bit unsure...unless one is ground and the other two go to the controller?

 

I have a 3-wire DC motor that looks like this. One wire (green/yellow) is CHASSIS. The other two (blue and brown) is DC power. The other set of three wires is a tachometer output.

View attachment 308145

my motor is a bit different in looks than that one...so not sure there ??

 

my motor is a bit different in looks than that one...so not sure there ??

Show us a picture of your motor.

 

Also, tell us what markings (if any) there are on the motor.

 

You will find some explanation here. https://howtomechatronics.com/how-it-works/how-brushless-motor-and-esc-work/
There are two types of commutation for what is essentially the same motor, BLDC and 3ph ECM motors.
The difference is in the way they are commutated.
The BLDC has only two windings energized at the same time whereas the 3ph version has all three powered.
You need a suitable controller, although some versions have the controller built in, as is often seen in HVAC motors.

That is a really neat site. if I understand it looks like I would need a controller with 3wires not two...I like the picture showing what I think of as one way resistors, but I would have thought the motor would still need be "grounded"?? I didn't pay attention to the HVAC motors...that they would have the controller built in, but that makes sense now that they would. Very interesting, I will have to dig deeper here for more knowledge!

 

My battery powered lawn mower needed a new blade. I could not find an exact replacement. The one I bought was intended to rotate in the opposite direction. I just switched the two wires going to the motor.

 

MEASURING the resistance between wires will clarify if it is a BLDC or not. Looking to see if one is green or green/yellow will also help. Would a battery powered motor need a frame ground connection on a battery only device??

 

That is a really neat site. if I understand it looks like I would need a controller with 3wires not two...I like the picture showing what I think of as one way resistors, but I would have thought the motor would still need be "grounded"?? I didn't pay attention to the HVAC motors...that they would have the controller built in, but that makes sense now that they would. Very interesting, I will have to dig deeper here for more knowledge!

If it has 3 wires then most likely no built in controller, it is simple to test, place a volt meter across all combinations of the 3 wires and give the rotor a spin and you should see a generated signal on all three.
In a portable situation, with no AC mains power involved, it should not need a ground, There will be no other reference for it!
On some BLDC motor you would see 3 other smaller conductors for the commutation sensors.

 

UPDATE! Very interesting to say the least. As many of the video's on utube have found. Water is the demon and some darn how way it gets inside the so called protective metal box. However moving forward...and funny even me in this tread is now moving away from the motor topic to the controller and other factors! LOL...mainly because without the controller there's not much of a way to test the motor alone as to see if it's still good and works. But...the motors are actually very not likely to be an issue on these anyway. On these lawnmowers there are safety switches/sensors and they are known to be an issue at times making the Controller not do it's job.."in the name of safety" they say. It's very wise to give these a look. Found that they are using black as a loop like they use white on lawntractors...then the other wires are color coded, one color for the safe bar(on/off) start button, speed, and if have power wheels. It pays to know the colors as they go to the controller and then it's clear how the board in the controller is running the machine. The really cool part of this is....ebay through china...u can buy a controller for under 20.00!! but U must know your wire hookups! While on ebay another really cool thing is they selling a box tester that tests controller, Hall, Motor and more! that's like 12.00 and it's mainly made for E bikes. I'm buying the cheap controllers and "hard wire" them in for their use and will most likely be able to keep all the "safety" intact! Note, if U have self propelled there will be two boards...one is a driver board for the self propelled motor and then the normal controller for blade motor and it's safety on off stuff. If U are a quick study U will figure out how it all works in no time, having the circuit board exposed helps greatly! I still have one baffle to solve. It's that tiny single wire from the 40volt battery. Of course there's the red thick for positive..and the black thick for negative...that's easy. but this tiny orange wire goes alone to the circuit board ...I thought it was for overheat and it would shut things down till it cooled...but then I noticed in cordless tools it would power the led light. I wonder if perhaps it "powers" the other side of the circuit board like maybe 5v so other things can work or function and no transformer is needed to break down the 40v??? Still looking for this answer as of yet.... Thanks all for your two cents....it was worth more than that!

 

Indeed "safety" systems are an area that often malfunctions and makes a system rather challenging to use for a different application. Of course, the safety systems are intended to protect the fool who would stick their hand into the path of a rotating mower blade and then complain that they did not know it was dangerous.

 

Indeed "safety" systems are an area that often malfunctions and makes a system rather challenging to use for a different application. Of course, the safety systems are intended to protect the fool who would stick their hand into the path of a rotating mower blade and then complain that they did not know it was dangerous.

yes, I actually do not fault most safety measures, they seem to need to be in place for those "fools"
Me, on the other hand been on the farm for ....well... let one guess thy age...point...We have mostly very reliable machines...and they never had a safety measure of any kind and I still have all my fingers and toes. But we've got 12 dummies on a jury and they reward a ...not so bright...person for hot coffee between legs!??? I say no more

 

UPDATE; Back on topic about those other spots on the 40V batttery by Ryobi. It has been confirmed that the T1 and the T2 are Temp ports. Once that was said online, I said "ok" then one is for the battery to communicate with the charger so that it will not try to charge a battery that may be too hot? yes, that would be T1.(perhaps with some other communication factors) So what is left is the mystery of the T2 and why it's connected to the controller with that orange one and only wire!!?? Still no answer as to ..is the battery communicating to the controller....or is the controller communicating to the battery!!?? I did find this site and it's the only mention that I've found in a deep dive...I'm still looking for this answer however! Here was what was said in this site. take a look at the second post in this line, thanks...any thoughts?????????

Ryobi 40V BMS troubleshooting and repair | DIY Electric Car Forums

 

Monitoring battery temperature during use is prudent, as is monitoring MOTOR temperature. OVERHEATING a cheaply made motor is probably rather common.

 

Monitoring battery temperature during use is prudent, as is monitoring MOTOR temperature. OVERHEATING a cheaply made motor is probably rather common.

While I agree with some of your comment, it's mute to what I want to know. I'm getting a clear picture that the T1 is for the charger to understand NOT to charge battery when it's warm or hot...that's wonderful! Let me also add...these motors do not seem "cheaply" made. They've got some cajónes'...and don't try to buy a replacement one for these...OUCH on the $$= not cheap!

However, the T2 goes to the controller with only one wire on the side of the circuit board where the safety wires hang out. I do not see where the motor if it got hot could inform the controller or the T2 area on battery that's it's getting hot, so your idea that it's monitoring the motor's temp?? I am NOT finding ANY site or person who for a fact...says...T2 has the ability to shut down the mower...in fact...the guy in the link I provided above said that the T2 is not hooked up to Ryobi blowers...?? only to other things such as the push lawnmower. Now ...this is something I found interesting yesterday pushing...FORCING a push mower into the pile of leaves...the mower REV'd up!!! just like a gov would do on a gas mower!! What if that T2 spot is acting like a Gov? when I pushed the mower and it bogged down, the motor = controller knew that..so it rev'd up to compensate for the bog....??? another words the T2 is a sensor of sorts...and when it feels a decline...a draw on the normal running current...it tells the battery...hey ya gettin' bogged down...provide a little more juice to get out of that jam!?? I felt the battery, controller and motor just to see if they got warm or hot during this experiment...they did not.... Bottom line....I need MORE PROOF.....to EXACTLY what that little one tiny orange wire does from the T spot on the battery!??????or...even better...what is it doing hooked into that Controller!!!??