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Hi all,
I have a motor to make an application such as vechile robot or anything to control it using PIC , but first i need to know all information about the motor I take it from my friend, the motor has 6 wires for motor and 2 wires for magnetic brake (24V) , I need to know these questions?
1- Is this motor AC or DC ?
2- what does the schematic mean ?
3- is there anyway to control the motion of each wheel ?
I attached the photos of this motor
thanks alot for any helping
Are any of the wires marked in a fashion similar or identical to the schematic?
Where did you get the schematic, was it in or on the motor ?
Do you have an adjustable power supply to test these with? It would be unwise to hook any wires to the Mains supply without some means of reducing both current and voltage, until you are sure of the wiring.
All that said, if the schematic actually goes to this motor, then likely it is a guide to change the motor's direction or operating voltage or both, that is pretty typical of A/C induction motors.
ALSO A/C induction motors usually require a rather large capacitor to enable them to start. Have you disassembled one or these ? If so, where do the wires go? Do you know what these were originally used for?
Other than the schematic, do you have any evidence to indicate these are A/C motors?
If these are A/c motors, how YA going to make a robot out of them? Maybe cheaper to adapt a D/C motor to the gear box.
One more question, are there any markings on the motor, Maker, MOD. #, Serial Number ?
Looks like a high-ish voltage standard DC motor (probably actually a universal motor) to me, 2 posts for the field, 2 posts for the armature, swap F1/F2 or A1/A2 to change direction, change speed with a PWM controller. Could control speed by changing voltage/current, but PWM is much more efficient.Quote:
Originally Posted by iugmoh
You probably would've found a lot of this information had you search the forums I pointed you to in one of your earlier threads...
I think skimask is correct.
I will also add the two wires coming out of the end are for speed feed back, a tach of sorts. These normally go to the speed controller. Say you have a conveyor with a variable load. Those two wires is how the controller knows what speed things are running at.
Yep , that jibes, F = field A= armature DOH !
Field and Armature wired in series, wired for CW and CCW. Sometimes I just overthink some things, what do you suppose the extra 2 wires are for? TACH ?
The O/P said 6 wires for the motor, 2 for brake, so I assume that's 8 wires total.
If that's the case, then yes, I'd say 2 for field, 2 for armature, 2 for tach, 2 for brake.
Damn! :)Quote:
Originally Posted by skimask
Isn't that what I said? :DQuote:
Originally Posted by Joe S.
Maybe this is it. Explains the 6 wires from the motor.
From the Baldor web site.
Attachment 2806
thanks for all, the information I talked about are found on a name plate on the motor, there are 6 wires on group and at the end of shaft are two wires for magnetic brake
If all that is on the name plate? What is the make and model of the motor? (Joe already asked this).Quote:
Originally Posted by iugmoh
Can you take a picture of the name plate?
You're good ! Even looks like a cousin to his schematic.Quote:
Originally Posted by mackrackit
oky I know sure that it's a DC series wounding motor. but why the schematic is two sections not one section ?
Not quite sure what you mean.Quote:
Originally Posted by iugmoh
Most any motor can be wired at least two different ways, there will be combinations for voltage and rotation. Providing a couple of the common hooks with the motor is normal for most manufactures.
This motor could be manufactured for an OEM, the OEM may put their own tag on and that tag may not have the same information as the manufacture would.
The voltage still bugs me. Most DC motors like this are 90 or 180 volt. If it is an OEM...
If I were you, I would take the motor to a re-wind shop. There they can test and label the leads and tell you all you want to know about it.
Just be careful with DC voltage that high. In my opinion it is more dangerous than AC. Before a bunch of people start debating that I will say other than a personal ZAP or two, with AC there is the zero crossing thing. If you are lucky, that is when you can break free. DC has zero, zero crossing. Now I will get off the soap box :)
If it really is a DC motor and you need help with a driver, let us know.
oky today I made some expeiments on the motor, I opened it and I determined the the two wires connected to brushes to be the armature coil using digital multimeter, then also determined the two wires for the field coil, then I connected them on series and applied DC voltage and it rotated without any problems, but the strange thing is the other two wires rest I don't know for what they are , I measure the ohm resistance between them which is 0.8 ohm but between the armature about 5.6 ohm and between the field 2.9 ohm , and also the cross sectional area of the armature and field are the same but for the other two wires (0.8 ohm ) is lesser than the armature and filed wire.
I applied a small voltage on these two wires (0.8 ohm) but this make sparking.
I measured the DC voltage and ac voltage between them during rotation of motor but the reading always is zero.
so what may be the purpose of these two wires ?
Back lighting? :DQuote:
Originally Posted by iugmoh
Seriously...it might be that you have to apply a small voltage to one of these wires in order to get a tach output from the other one... Who knows...
may be, but I think that this motor is for a vechile and there was a controller to control each whell alone , my be these two wires is to control any wheel to to stop it inorder to stop one and rotate one to change the direction of vechile. the strange thing also in these twol wheels is when I rotate any of these two wheels in any direction the other rotate in the oposite direction.
Not strange...normal. There's like an open differential in between the 2 just like most rear wheel drive automobiles...Quote:
Originally Posted by iugmoh
And the whole direction changing thing is most likely NOT done inside the motor.
sory I mean by this when I rotate by hand but when apply dc voltage the two wheels are rotated in the same directionQuote:
Originally Posted by iugmoh
Which is exactly the way an 'open differential' on a rear wheel drive car works.Quote:
Originally Posted by iugmoh
Google it...
thanks alot skimask for your interesting information, I learn new things about open differential , I read it but I can't distinguish between straight and turn mechanisms and what happened and what is the thing make this machanisms straight or turn.
http://auto.howstuffworks.com/differential2.htm
It is a bit difficult to picture without actually seeing it in operation.Quote:
Originally Posted by iugmoh
Take the gear case cover off if you can, turn it and play with it.
As soon as you see it in operation, it'll all make sense...(or maybe go to an auto mechanic shop and see if they've got one to show you or something)
EDIT: I just took another look at the pictures in post #1. An open diff is exactly what it looks like to me. The motor input is slightly offset from center, the round bump on the one side is for the large bevel/ring gear, probably driven off a center mounted reduction gear setup, the spiders and side gear are probably mounted in the middle.
You never did mention exactly what this motor was from. I could be a wheelchair setup as long as it has a sort separate steering motor, unless the brakes actually accomplish the steering.
some motors, ac and dc have little thermal switches in them that open when the motor gets too hot so people don't burn up.
don
amgen
Picture 2 half circles, for instance #1 having a radias of 500mm and #2 having a radias of 400mm, and both having the same exact center. now imagine those 2 half circles represent the tracks left by the wheels. the inner wheel travels a shorter distance than the outer wheel does. That is the purpose of the "open differential" . Does your motor have 1 set of 2 or 2 sets of 2 brushes? BTW a brushed motor is commonly referred to as a Universal motor as it can operate from A/C or D/C.Quote:
Originally Posted by iugmoh
I still think there is a good chance it is a compound motor.Quote:
Originally Posted by iugmoh
http://www.joliettech.com/connections_dc_motors.htm
and yes the motor might turn with out the series winding hooked up, and yes if you applied voltage directly to these lead it very well could become skimasks backlight :)
Here is some fun reading, the second half is DC.
http://www.reliance.com/mtr/mtrthrmn.htm
I don't believe that statement is entirely accurate.Quote:
Originally Posted by Joe S.
Take one of those little hobby motors for R/C cars...
Put A/C on one of those and it'll just sit there a jiggle...depending on the A/C frequency of course...and the voltage...as stated above it could become a backlight...and a short term heater...and possibly a insect defogger...or get rid of annoying kids...
I should have excluded PM motors from that statement as ski pointed out make good space heaters on A/C.Quote:
Originally Posted by skimask
You may well be right! Time to disassemble and inspect to see what he has, I hope he has some experience with brushes and commutators.Quote:
Originally Posted by mackrackit
In an automotive differential, you have 4 pinions or "spider gears" 2 of which are attached to either axle. the other two are driven by the carrier through the common shaft which goes through the carrier. The carrier is driven by an attached Ring and Pinion set which allows for a 90 degree change in direction of power. the 4 pinions or spider gears are in constant mesh and as the assembly is rotated by the carrier around the axles axis, it allows the axles to turn at a constantly changing ratio from zero difference to 100% difference depending upon the load applied to each. If one wheel loses traction that wheel will spin wildly, while the other wheel remains motionless.Quote:
Originally Posted by iugmoh
Clear as MUD!Quote:
Originally Posted by Joe S.
Technically accurate description, just a pain to visualize...
thanks for all, all things about my dc motor is now clear , the other two wires are for thermal protection , and in this motor you can't control speed of each wheel alone electrically, but there are hand break near each wheel which you can use to slow one wheel to steering the motor to other direction.
What's the matter, not enough colons?Quote:
Originally Posted by skimask
http://www.youtube.com/watch?v=FKaF20iFU9s&NR=1
The 2 extra wires actually connect directly to the Turbo-Encabulator...
http://www.youtube.com/watch?v=9k9x2gUHbQs
I have this question ?
Is't possible to run a series wound motor as separately excited or shunt excited motor ? by applying for example a dc voltage on field coil to be separatley excited , or it's designing to work for specific type ?
I do not think it would run. Something tells me that if it would run, you would not have much power.
Map out the coils, a certain type from different manufactures may be able to be modified differently.
Sorry for the vague answer.
return back after I run the motor on, by convert it from series to separately excited by applying about 1.5V to it's Rf and variable voltage at Ra and it's working well.
now I build a driver for a gate of MOSFET from 5V to 12V and generate PWM to this driver to control the speed of motor by changing the voltage at Ra. the mosfet driver will switching 110 Volt to Ra, when I applied 12V or 24V no problem but when I applied 110V to MOSFET(IRF640) It's damaged and it's the second one I don't know why since this mosfet is capable to handle 200V , 18A.
So I need to make 110V driver can handle this voltage and current , anyone can helo me ? I attached the schematic
Remove the zener diode (D3). It will limit the gate voltage to 9.1 volts not enough for the mosfet total conduction.
It is the case to use a flyback diode across the motor
Al.
Why do complicated while life could be way easier... if the goal is just to drive motor(inductive load) with PWM, the above circuit have few problem indeed. I would never use a Mosfet without a MOSFET driver IC, or without any Push-Pull setup... at least for high current load...
Still doable to use Logic level Mosfet directly connected to the PIC.
Thanks aratti and mister for your replies, I remove the zener after it's damaged and I'm putting the flyback diode , I know that IC drivers is better than I make a driver alone , but in our country It's a big problem to get IC's from any country because there are problems in ports and transportation.
Is there a professional circuit for mosfet gate driver and driver for mosfet handling 110V and 3A please help !
aratti,
what is wrong with D3 in general ? It is good to protect gate to less than 20v although the driver is only 12v. Also I think that the free-wheeling diode across the motor has to be a FAST SWITCHING type, otherwise the diode will not totally limit the fly-back voltage to the mosfet.
don
amgen