Problem_Very simple question, but very strange realty!

Thread Starter

Haytham_Salem

Joined Jun 29, 2018
6
Hellow all engineers,

i have a very strange problem for me
it is a simple coil of a dynamometer , it's resistance = 190 Ohm
when i apply a DC voltage = 25 volts
it must drive a current = 131.6 mA
but !!!!!!!!!!!!!!!
in my case the current = 7.5 mA

please someone tell me how come is it??
 
Last edited:

ebeowulf17

Joined Aug 12, 2014
2,942
Thanks for your quick response ,
i have tried to use so many power supplies
1- the ps of the machine (it is working good).
2- PC psu.
3- other types.
Have you measured the resistance yourself, or is that just a claimed spec?

Also, have you measured 25V across the coil while you were testing it, or is 25V the supply voltage before you connect the coil?
 

Thread Starter

Haytham_Salem

Joined Jun 29, 2018
6
Have you measured the resistance yourself, or is that just a claimed spec?

Also, have you measured 25V across the coil while you were testing it, or is 25V the supply voltage before you connect the coil?
yes, i have measured the resistance myself
i have measured 25V across the PS before the test ,
i tried to measure across the coil during the test by simple PS = not 25 i thought that is because voltage drop on the AVO (!!!)
but i remembered
when i have measured the voltage across the machine PS terminals there was no variation in the volt (when i tried to rise the volt from 0 to 25 or more just the machine max. voltage appears) in the case of this coil
but !!!!
in another dynamo-meter coil (working good) there was a voltage variation

this is my machine
https://www.magtrol.com/wp-content/uploads/dsp6001manual.pdf
in this case my coil PS called "Hysteresis Brake"
 

Danko

Joined Nov 22, 2017
791
Hellow all engineers,

i have a very strange problem for me
it is a simple coil of a dynamometer , it's resistance = 190 Ohm
when i apply a DC voltage = 25 volts
it must drive a current = 131.6 mA
but !!!!!!!!!!!!!!!
in my case the current = 7.5 mA

please someone tell me how come is it??
Resolder magnet wires joints with outer leads and coil will work as new one.
 
Last edited:
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