I figure a lot of you must be getting really bored with making pulse motors. Here is a different kind of motor that looks like it would be a real challenge to build, and challenge equals fun:
http://en.wikipedia.org/wiki/Universal_motor
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The universal motor is a type of electric motor that can operate on both AC and DC power. They are commutated series-wound motors where the stator's field coils are connected in series with the rotor windings through a commutator. This type of electric motor can operate well on AC because the current in both the field coils and the armature (and the resultant magnetic fields) will alternate (reverse polarity) in synchronism with the supply. Hence the resulting mechanical force will occur in a consistent direction of rotation, independent of the direction of applied voltage, but determined by the commutator and polarity of the field coils.
Universal motors have high starting torque, run at high speed and are lightweight and are commonly used in portable and domestic equipment.[1] They're also relatively easy to electronically control. However, the commutator has brushes that wear, so they are much less often used for equipment that is in continuous use. In addition, partly because of the commutator universal motors are typically very noisy.
When used with AC power these types of motors are able to run at a rotation frequency well above that of the mains supply, and because most electric motor properties improve with speed, this means they can be lightweight and powerful.
One useful property of having the field windings in series with the rotor windings is that as the speed increases the back EMF naturally reduces the voltage across, and current through the field windings, giving field weakening at high speeds. This means that the motor does not inherently have a maximum speed for any particular applied voltage. Universal motors can be and are generally run at high speeds. By way of contrast, induction motors cannot turn a shaft faster than allowed by the power line frequency.
Motor damage may occur from over-speeding (running at a rotational speed in excess of design limits) if the unit is operated with no significant mechanical load. On larger motors, sudden loss of load is to be avoided, and the possibility of such an occurrence is incorporated into the motor's protection and control schemes. In some smaller applications, a fan blade attached to the shaft often acts as an artificial load to limit the motor speed to a safe level, as well as a means to circulate cooling airflow over the armature and field windings.
An advantage of the universal motor is that AC supplies may be used on motors which have some characteristics more common in DC motors, specifically high starting torque and very compact design if high running speeds are used.
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Variety is the spice of life....
What would be the approximate efficiency of the motor in the pic of the wiki article? The one I am getting for the electric Fiero conversion is a constant torque type such as this also. Warp9. It can be run way beyond its data sheet ratings. The sheet says 72v. Some guys are running them on 300v with 1000A controllers. Im going to be using the automatic 3 speed trans. It is recommended to use a manual transmission and just leave it in 3rd or 4th gear as these motors have tremendous torque in the bottom end that taking off in 4th is like a high speed golf cart. But that seems to be an awful waste of power to try and accelerate in such a gear. So im going to take advantage of the leverage that the auto affords me.
So I have the 9in motor, keeping the tranny, with the CV axles, all together to motor the car. From the motor to the wheels is not a great efficiency transfer, even with the 2.8 V6.
What I would like to see is the motors built into the wheels. Some companies have already used them and are beginning to use them in cars and bikes. A friend of mine at work used to work in the mines in Peru. The giant dump truck, im sure some here have seen them or pics of, and this was back in the 70s he says, the drive motors were electric built into the wheels. ;) He helped repair them.
There must be a good reason for doing so. ;) And it would be difficult to do so with the "universal motor" without gearing, of which we lose eff.
Here is some of the insides of my Tidalforce M750 bike. It is regulated to 20mph and 749w(just under 1hp) to be street legal in all 50 states federally. Some states allow more, but could be illegal if confronted by a fed. ??? The m750x is 1kw and 30mph They both run off of 30 nimh D cells in the front wheel hub capable of 36v and 50a cont. 100 amps peak. The pack is fused at 80 amps.
This motor is optically triggered, asymmetrical 16 magnets and 14 coils operated in 7 pairs. The difference between the m750 and the m750x is all in programming. No other differences.
My trek bike has a front hub kit. Its smaller in diameter than the M750 motor and has 52 coils and 52 magnets, symmetrical. Tiny mags 1x 1/2x 1/8 triggered by hall sensor.
For me, the universal motor is not the most efficient way to go. In many useful cases they need some gearing which creates losses. Unless its a fan. ;) Some of those use belt drives, larger ones.
There is a reason that more and more motors are using permanent mags instead of coils. And its not because the mags are cheaper than the copper needed. ;) And brushes are really becoming old school, wouldnt ya say? ;D
Mags
MH
Thanks for the offer,however some folks are addicted to pulse motors...
Pulseaholics anonymous is sponsering an event At TinMans Place
A pulse motor build Off, No holds Barred Or restrictions [as apposed to previous years "themes"]
I understand its even "sanctioned" and sponsered by some very heavy hitters in the field....the who's who Of Pulseaholics will be there
[date to be forthcoming]
@Mags
Shhe is one sweet Motor yah got there... I like the "hub" concept
for a nice light chassis !!
Thx
Chet
@MileHigh
The universal motor is a pulsed motor-infact every DC motor runs on electromagnetic pulses,as dose AC brushed motor's.A universal motor can be rewired to be more efficient than any other electric motor out there.
Pulse motors ruel.
http://www.youtube.com/watch?v=szpJ97M58G4
Hi tinman,
great motor, test idea and video! thanks for sharing it.
Your modified motor seems to be over 60% more efficient at turning the fan then the universal motor designed for it.
Should a universal motor not be in the 70 to 80% efficiency range already?... if so, how can such a large difference be?
Can someone please explain what I'm missing here ::)
Thanks
Luc
Such an universal motor could be driven with this http://www.intersil.com/content/dam/Intersil/documents/fn36/fn3659.pdf (http://www.intersil.com/content/dam/Intersil/documents/fn36/fn3659.pdf) (HIP4081A, 80V/2.5A Peak, High Frequency Full Bridge FET Driver).
There a similar drivers for higher loads.
For me these brushless outrunners http://www.conrad.at/ce/de/product/231867/Robbe-Roxxy-BL-Outrunner-2824-34-7-12-V-Umin-pro-Volt-1100-Turns (http://www.conrad.at/ce/de/product/231867/Robbe-Roxxy-BL-Outrunner-2824-34-7-12-V-Umin-pro-Volt-1100-Turns) are interesting. Of course there are numerous drivers on the market. But coming up with a new (and hopefully more efficient) way of rewinding and driving them could be fun.
One should not dismantle these brushless motors. The description of the one I have got says, that it can never be reassembled by hand (has to be done with some machine or special alignment tool).
Greetings, Conrad
A YouTube user called DadHav just published an interesting video about driving brushless motors:
http://www.youtube.com/watch?v=8b4xlCKn3LQ
The demonstrated and fully disclosed circuits are worth studying.
Greetings, Conrad
Starting in the late 1970s there was the introduction of "direct drive" turntables. They were beautiful direct-drive brushless dead-silent servo motors. The platter was the rotor and there were flat induction coils in the base. I think the flat coils were laid out like radial wedge segments like when you slice an orange in two. It's been so many years since I looked at one I can't be sure. I think there was a magnetic tape head reading a magnetized stripe on the inside of the platter for the servo control. The magnetized stripe had an AC frequency encoded into it. There might be a microcontroller or some hard-wired logic to implement the servo control.
That might be a fun thing to hack into and re-purpose as a motor with a drive shaft where you could vary the speed by figuring out how to hack into the servo control system. If you did it right it should self-correct for the torque to maintain constant speed as you vary the load. If you could figure out how to amplify its feeble torque then you would have a mean variable-speed servo-controlled machine.
They actually should be quite cheap and relatively easy to find online or at Sally Ann or thrift stores. It's almost sacrilege when you think you might be able to buy a $350 1981 ultra-high-precision smart high-tech turntable for $20.
What I like about the universal motor is that it has brute-force torque when you first apply power. Thee is no counter-EMF on start-up so the current draw is high and away she goes. If you make one yourself you would be trying to balance the magnetic field generated in the stator coils with the magnetic filed generated in the rotor coils. So you are playing with core materials and core size and numbers of turns on both sides of the divide. A real balancing act.
ConRad
DadHav is a pulseaholic ....
I am quite sure he will be sporting his wares at the TinMans "pulse off".
These boyz Play hard ball .......and they have "mad" building skills!!
should be fun as well as enlightening ...
Plus they have Prizes !![real stuff, not lollipops and such]
thx
Chet
Quote from: gotoluc on April 25, 2013, 12:48:28 PM
Hi tinman,
great motor, test idea and video! thanks for sharing it.
Your modified motor seems to be over 60% more efficient at turning the fan then the universal motor designed for it.
Should a universal motor not be in the 70 to 80% efficiency range already?... if so, how can such a large difference be?
Can someone please explain what I'm missing here ::)
Thanks
Luc
Hi Luc
The house fan motor is an induction motor,not a universal motor.What you get off the shelf is never as good as it can be.It's just a mater of turning the magnetic field around,so as the lenz force effect helps rotation,not hinder it.
I will be continuing this project soon,but i am looking into this LENR stuff a lot at the moment,as it is the only thing i have been able to get to go over 100% efficiency.
Quote from: tinman on April 26, 2013, 07:40:58 AM
Hi Luc
The house fan motor is an induction motor,not a universal motor.What you get off the shelf is never as good as it can be.It's just a mater of turning the magnetic field around,so as the lenz force effect helps rotation,not hinder it.
I will be continuing this project soon,but i am looking into this LENR stuff a lot at the moment,as it is the only thing i have been able to get to go over 100% efficiency.
Thanks for the reply tinman,
So, is your motor an induction motor you modified to switch the magnetic field around, so the lenz force helps the rotation?
I would be interested in a link to information shared on this idea
Thanks for your time
Luc
Hi MileHigh,
I was wondering on those direct drive motors if the coils could be re-wired to create a one-way motor(?).
The magnets would be attached to a rotor outside the ring spaced/offset so they don't interfere with another attraction/repulsion coil. If possible both sides of the field could be used.
It would require strong rectangular magnets to generate enough EMF in the next coil and handle voltage drop from bridges. Small magnets would not generate enough EMF.
The bridges would allow the pulse to travel in one direction, the pulse only needs to be short enough but strong enough to pull and push the magnet from drive coil. This could be tweaked with a bleeder resistor if the coil maintains too great a field. Ideally it would be air core coils to reduce cogging. When a pulse in a bridge is in the reverse direction it acts as open circuit there should be no Lenz on the attraction or repulsion coils.
The theory anyways is that the faster it spins the greater the EMF generated in the coils creating more torque on the rotor. A flywheel may overcome some of the cogging/lenz drag once spun up to speed.
This is an untested idea.
Quote from: gotoluc on April 26, 2013, 12:04:26 PM
Thanks for the reply tinman,
So, is your motor an induction motor you modified to switch the magnetic field around, so the lenz force helps the rotation?
I would be interested in a link to information shared on this idea
Thanks for your time
Luc
Hi Luc
The motor i modified is a universal motor,the house fan motor is an induction motor.
Here is the link to the work on this modification.
http://iaec.forumco.com/topic.asp?TOPIC_ID=1040
Am I right that this type of motor, vacuum cleaner motors, would be
good for the Bedini Watson energiser setup:
Half way down
[/color][/color][/u]http://www.fight-4-truth.com/Schematics.html
"Image 13 - This is the famous John Bedini Free energy Genratior".
It is hard to find DC wound field motors with good quality bearings,
starter motors usually having particularly poor bearings.
DreamThinkBuild:
I am not 100% clear on what you are saying. It looks to me like you are speculating that when a drive coil pulses against a magnet to move it along the track, that the next coil in the series will see that moving magnet and act as a pick-up coil. I think that you are speculating that the energy picked up by the pick-up coil can be passed along to another coil acting as a drive coil to keep tings moving.
All that you really need to do is move a magent past a pick-up coil and make precise measurements of how how much mechanical energy it takes to move the magnet, and also make precise measurements of how much energy you can extract from the pick-up coil. You could try changing various parameters and look at your data. You could do similar tests where you energize a coil and make precise measurements of how much energy you put into the coil and then make precise measurements of how much energy you can get back from the back-EMF spike. You don't necessarily need to have a fancy rotary/linear motor configuration. You want to eliminate all the complexities and just strip it down to the bare essentials to make your measurements.
If you did make these measurements they would confirm that there is no extra energy to be found in pick-up coils or beak-EMF spikes. Armed with that knowledge you could state that all sorts of fancy motor configurations are based on some pretty simple building blocks and then draw your own conclusions.
MileHigh