Than Wbahn.For experiment, I have taken out from the video cassette re-winder which we used many years back. I forgot to mentioned that I have used digital multimeter to measure the value of resistors rather than color codes.
I did not understand what DMM mean. DMM to directly measure the resistance of the motor's winding.Does this statement mean to measure the resistance of coil of motor without applying power? With understanding, I have measured resistance by touching one terminal of motor with red probe of meter and other terminal of mortar with black probe of meetr. Then the reading is 8.5 ohms.

NB: if i have done the correct way then. At 6.5mA, that the winding is roughly 15Ω. (as discussed ealier; when 1 volt is taken by motor winding. ie. R=v/I=1/6.5=15 Ohms

Your valuable suggestion or comments is anticipated.
Thanks

 

DMM - Digital Multi-Meter

It sounds like your earlier current measurements were with the meter shorting the motor, so you weren't measuring the motor current.

We've got a real conflict between the measurement that has 85mA going through the 100Ω resistor when it is in series with the motor but only about 0.25mA when the motor is connected directly.

Do you have a 10Ω resistor or anything in the general range?

 

Thanks Wbahn. I understoood the reasons. But you have not said about whether I have correctly measure the value of motor winding. In the mean time and with better understanding of circuit. I have tried to connect that 100 ohms in paralled,unlike earlier now motor is running.But with little reduce speed. I have also measure the ampere, and reading is 0.8 mA. where as without resistor in parrall the motor is drawing less current ie 0.25 mA. I have no idea why it is happening. Im not sure if my way of measuring current in parallel is right or not

Yes I have only 15 Ohms resistor. I dont have 10 ohms.

Thank you La

 

I suspect you are misreading the range. It is probably .25A, not mA.

Bob

 

Thanks Wbahn. I understoood the reasons. But you have not said about whether I have correctly measure the value of motor winding. In the mean time and with better understanding of circuit. I have tried to connect that 100 ohms in paralled,unlike earlier now motor is running.But with little reduce speed. I have also measure the ampere, and reading is 0.8 mA. where as without resistor in parrall the motor is drawing less current ie 0.25 mA. I have no idea why it is happening. Im not sure if my way of measuring current in parallel is right or not

Yes I have only 15 Ohms resistor. I dont have 10 ohms.

Thank you La

It would really, really, really help if you could throw together some kind of a sketch of how you have things connected, including the meter, when you make these various measurements. Again, just some boxes and lines in Paint are more than adequate.

How you measured the motor winding resistance sounds okay.

Are you sure that your meter is on a mA scale and not an A scale? If it is autoranging, there should be some kind of a range indication on the display. Most meters today will actually display either "A" or "mA".

 

Dear Wbahn. Thank u. I have drawn drawing in paint and copied in to word. and from word i tried to copy in post message box. but doesn't work. I tried to insert image, but message pop up for only URL link. So i could not send u the illustrative picture. With regard to DMM setting I have selected Auto range. When the reading appeeared, the meter is on mA scale.

Thank you

 

Dear Wbahn. Thank u. I have drawn drawing in paint and copied in to word. and from word i tried to copy in post message box. but doesn't work. I tried to insert image, but message pop up for only URL link. So i could not send u the illustrative picture. With regard to DMM setting I have selected Auto range. When the reading appeeared, the meter is on mA scale.

Thank you

Under the Quick Reply Message Box is a button labeled Go Advanced; click on it. In the new Message Box, click on the Paper Clip in the top line. A Pop-up window will allow you to upload image files. When you have selected the file, click the Upload Button on the right (you may need to scroll to the right). After the upload, you can close the Pop-up Window. Write your message and press the Submit Reply Button.

 

Thank u LDC3. I have converted the file to PDF format and attached for Wbahn and u all to see if i have done the right way or not

 

There is also a preview button to check your post.

Have another go, you should have seen a box marked 'manage attachments'
There is a size limit for all file types.
Make sure yours is small enough or it will not be accepted by the system.