I have a vintage megawattmeter. It is able to indicate values from -1 to 7 MW. I wish to be able to provoke it to display any value I want, preferably without actually generating megawatts of power.
If I understand this correctly, it means that both power and voltage are transformed down, from max. 1000A to max. 5A, and max. 6000V to max. 110V. The first symbol seems to indicated that two phases out of three are used for the measurement?
There are 7 Connections on the meter, numbered from 1 to 7. If I understand the diagram correctly, this means that connection should be like this:
- phase 1 current in (k) - low voltage
- phase 1 voltage - low current
- phase 1 current out (l) - low voltage
- phase 2 current in (k) - low voltage
- phase 2 voltage - low current
- phase 2 current out (l) - low voltage
What would be a good way to control this meter to display my desired values?
Update: added some additional pictures and descriptions
I was able to open up the instrument. As far as I can judge, connections 1 and 3 go to one big coil, 5 and 7 go to the other big coil. Connection 4 goes to the chassis of the big coil that has the needle. Connections 2 and 6 go to each of the two smaller coils, and from each of the other ends of those coils, there are wires to the needle mount and the moving element in the other big coil. See pictures below. I'm still not sure how I Shield proceeed to get it to actually show the values I want.
I tried to measure L and R. Wasn't able to find C.
- Across 1-3 R 0.3 ohm L 0.5 H
- Across 5-7 R 0.3 ohm L 0.4 H
- Across 2-6 R 1878 ohm L -4 H
- Across 2-4 R 225 ohm