• raghunathreddy36

MemberJan 28, 2010

two positive terminals is given to D.C Motor

if D.C. supply of two positive terminals gifven to the D.C. motor, what action takes place ?
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Replies
• MemberJan 28, 2010

Nothing will happen.

There should be a closed loop for the current to pass! so if nothing is passing then there will be 0 current so i guess nothing happens.

PS. Why do you want to do this?
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• MemberJan 29, 2010

No current can pass through without a Potential difference.
In some cases the two motor terminals can be positive to a given common ground, but the motor will operate only when the motor terminal voltage has a difference high enough to cause the motor to react. In this case the terminal voltage seen by the motor is +ve and -ve, even though they can be positive to another given ground reference

Rifaa
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• MemberJan 29, 2010

I think the windings of motor will burn!!
the current provided to the motor will be unable to find the proper path to leave, since both the potentials are positive therefore a less amount of current will flow out from the less positive potential thus results in improper rotation and it cause over heating of the windings!!
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• MemberJan 29, 2010

imnitsy
I think the windings of motor will burn!!
the current provided to the motor will be unable to find the proper path to leave, since both the potentials are positive therefore a less amount of current will flow out from the less positive potential thus results in improper rotation and it cause over heating of the windings!!
IT WON'T !! Don't believe me.
That's because you don't have any experience on that matter.

Rifaa
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• MemberJan 29, 2010

imnitsy
I think the windings of motor will burn!!
the current provided to the motor will be unable to find the proper path to leave, since both the potentials are positive therefore a less amount of current will flow out from the less positive potential thus results in improper rotation and it cause over heating of the windings!!
It will not!

There is no current which is passing so no buring nothing!
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• MemberJan 29, 2010

Nothing will happen.Because two positive singal means no closed loop circuit(one positive and negative is closed loop)therefore no current passes through the winding.Dc motor still idle.
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• MemberJan 29, 2010

Sheeesh ! guys.
None of u have any experience on these type of matters, right.
Motor will operate exactly stated in my reply.

Rifaa
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• MemberJan 29, 2010

Rifaa
Sheeesh ! guys.
None of u have any experience on these type of matters, right.
Motor will operate exactly stated in my reply.

Rifaa
thats what i said!!
the motor will work but very inefficeintly, and probably the winding will get burn due to over heating!!😉
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• MemberJan 29, 2010

imnitsy
thats what i said!!
the motor will work but very inefficeintly, and probably the winding will get burn due to over heating!!😉
Ding! Ding! Ding!Ding!Ding!Ding!wrong!!!! 😁

Motor won't burn as long as the motor terminal voltage does not exceed it's rating.
Motor will operate normally..

Rifaa
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• MemberJan 30, 2010

I said it wont work!! but that's partially correct though!!

I go with Rifaa , if there is potential difference the motor runs probably!!

But can some one tell me how the circuit will become a closed loop?

I have some confusion , practically assuming it I dont get the closed loop..
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• MemberJan 30, 2010

Can u imagine a PSU with multiple out puts, say 12V , 5V with a common -ve.
If you can, then tell me what is the difference between the two positive voltage?

Rifaa
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• MemberJan 30, 2010

i think the motor will run only if it will give some potential across the two terminal.if the two positive terminal can cause a closed loop through the motor armature then it can happen.but its quite difficult because the armature coils can burn with excss heat
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• MemberJan 30, 2010

😁ya thats right if there is no closed loop than current will not find any returning path..but if the two terminals find +va and -ve wrt. reference (say ground) than motor can be operated...
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• MemberJan 30, 2010

ya.i agree wit rifa.........imnitsy i think u must fiirst better read the concepts of eletrostatics n current electricity., first it needs to give the minimum voltage to operate motor..on the other hand you are appling two positive voltage which finally reduces the net potential difference applied...
so how come it will damage buddy, if that p.d is not more enough to drive the motor even...!!
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• MemberJan 30, 2010

i got my mistake, closed loop should be there..n for getting that we must have a single source or multiple source connected together..to form a closed loop
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• MemberJan 30, 2010

at least some one have an idea on motor practical application.
Newbies, if u are not sure then don't make judgments. learn from the experienced ones.
That's why we are here.

Rifaa
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• MemberJan 30, 2010

i think it won't work
because for functioning of dc machines there should be polarities of +ve n -ve s. if u are able to do so it w'ld be miracle, best of luck to you for your innovative idea
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• MemberJan 30, 2010

Rifaa

is it really run?.You confused me even though I have not tried this test

It should be open circuit anyhow i need some clarification
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• MemberJan 30, 2010

rasu3045
Rifaa

is it really run?.You confused me even though I have not tried this test

It should be open circuit anyhow i need some clarification
i guess..it will not work and it will never form a closed loop..if there are two positive supply of different magnitude from different sources

as ,the voltage source is a type of source in which energy is stored in the form of voltage so its output is voltage,,,and the power and energy are always in the form of force,,so voltage must be a force..and i guess for producing an emf on output terminals of the battery, internally there should be a closed path(high resistance)..i mean like in electrochemical cells.which pushes the electrons from negative termical..through output path(load) to transfer the energy(or say electrons) between electrodes of cell

so i guess if we give positive suppy from two different sources of different magnitude..still it be open circuit
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• MemberJan 31, 2010

Thanks Rifaa!!

I understood the concept behind it!!
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• MemberFeb 1, 2010

For those dummies out there. Read carefully 😉

First thing is to learn about dual supply capable PSU's, or even with triple out puts, or what ever that is.

Supplies with more than one out put have different voltage levels, for example , take dual voltage one with a 12V and a 5 volt. They should have a common ground which makes it a common reference to the two +ve voltages. A DMM connected to to -ve and +12V will give +12V, now if u wish to measure the +ve 5V, u would just move the +ve meter lead. which is common sense. Now comes the tricky part, if the ground is not common to both rails, one +ve side will read zero, both rails will give a reading only if both +ve rails shares a common ground.

Now if u were to put the meter at the both +5V and +12V, the meter will give a reading of +7V. Provided u connect the -ve terminal of the DMM to +5V and +ve terminal to +12V. If you reverse them you would get -7V.
But the problem is this reading is only possible if the rails shares a common ground. If not meter reading will be zero, which gives you "YOUR" closed loop.

Now if you were to connect a motor with a voltage rating close to +7V.
What would happen.
From here I will let your imagination run wild.

Peace 😁

Rifaa
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• MemberFeb 1, 2010

i can not understand you answers
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• MemberFeb 2, 2010

raghunathreddy36
i can not understand you answers
Then I donno what to say. Can't make it simpler than this

Rifaa
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