Question about shunt information

[Dialtone]

Hope someone here can explain some of the rating info on current shunts.
I have 2 different ones.
1 is 200 amp 75mv, the other is 150 amp 50mv.
Can someone explain what the mv rating means?
As an example, I took a reading on the 150 amp 50mv one that showed about 4-5 amps on the meter and a digital multi-meter read 1.4mv across the shunt.
How does this correlate?
Thanks

 

[k7elp60]

What it means is that when 200amps is flowing thru the 75mv shunt, there will be 75mv(.075 volts) across the shunt. It's actual resistance is R=E/I or
.075/200 = .000375 ohms. The other one will have 50mv(milli-volts) across it when 150 amps is flowing thru it. Its resistance =.05/150 = .000333 ohms.
With 4 amps thru it the voltage would be E=IR E=.000333 X 4, E=1.333 milli-volts.

 

[kchriste]

I took a reading on the 150 amp 50mv one that showed about 4-5 amps on the meter and a digital multi-meter read 1.4mv across the shunt.

It means that there will be 50mv across the shunt when 150 amps flows though it. So.... This means that this particular shunt produces 0.3333mV per amp or 50mV/150A. So 4A = 0.333333 x 4 = 1.333333mV