David Fernandes
Member
How can you avoid dimming lighting while initially energizing equipment.
Dimming lighting???
- Thread starter David Fernandes
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David Fernandes
Member
A vacuum for instance.
David Fernandes
Member
Learning to live with it is probably the solution for an existing structure. I try to isolate lighting, power in new install.
charlietuna
Senior Member
Study up on VOLTAGE DROP and you'll begin to understand why the lamp dims.
stickboy1375
Senior Member
- Location
- Litchfield, CT
Learn to live with it would be my suggestion, a dedicated circuit will not necessary fix the dimming complaint.
Yea, but work is work, and work = money.:grin:
stickboy1375
Senior Member
- Location
- Litchfield, CT
Yeah, but what do you tell them when the lights still dim after plugging into a new $400 receptacle?
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
081224-1440 EST
The amount of change in voltage on the load side of a voltage source with some internal impedance from an addition of a load is relatively independent of the pre-existing load on the circuit if the said source impedance is small compared to the load. This is the general design of a power system.
In a typical application there is a source, pole transformer, with its source impedance. Also wires from the transformer to the main panel with their addition to the source impedance as seen at the main panel. Then there are many branch circuits running from the main panel.
Suppose the source impedance at the main panel and looking toward the transformer is 0.005 ohms. Then the drop in voltage as seen at the main panel is 0.05 V for a 10 A load. Startup current on a small motor might be 70 A and this would cause a drop in voltage of 0.35 V.
Next go to the end of a 50 ft run of #12 wire. This has a loop resistance of .16 ohms. 70 A thru this is a voltage drop of 11.2 V. If your lamp is at the end of the branch where the motor is also located, then you will see a substantial flicker. If you put the lamp on a different circuit, then it only experiences a change of 0.35 V and this is a much reduced flicker.
Note: Your voltage drop at the motor is actually 0.35 + 11.2.
.
The amount of change in voltage on the load side of a voltage source with some internal impedance from an addition of a load is relatively independent of the pre-existing load on the circuit if the said source impedance is small compared to the load. This is the general design of a power system.
In a typical application there is a source, pole transformer, with its source impedance. Also wires from the transformer to the main panel with their addition to the source impedance as seen at the main panel. Then there are many branch circuits running from the main panel.
Suppose the source impedance at the main panel and looking toward the transformer is 0.005 ohms. Then the drop in voltage as seen at the main panel is 0.05 V for a 10 A load. Startup current on a small motor might be 70 A and this would cause a drop in voltage of 0.35 V.
Next go to the end of a 50 ft run of #12 wire. This has a loop resistance of .16 ohms. 70 A thru this is a voltage drop of 11.2 V. If your lamp is at the end of the branch where the motor is also located, then you will see a substantial flicker. If you put the lamp on a different circuit, then it only experiences a change of 0.35 V and this is a much reduced flicker.
Note: Your voltage drop at the motor is actually 0.35 + 11.2.
.
charlietuna
Senior Member
What if you did a service upgrade and it still dimmed????? And then you found out it had a loose connection on the power company's transformer nuetral???????????????
More than likely, I would have found that well before I suggest a new circuit. I don't hunt squirrels with an elephant gun.
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steelersman
Senior Member
- Location
- Lake Ridge, VA
this would actually be the same as saying: "vacuum with the lights on"
Kdog76
Senior Member
- Location
- The Dairyland State
now I'm really confused. Doesn't take much.:smile:
steelersman
Senior Member
- Location
- Lake Ridge, VA
he had said for you too vacuum without the lights off. Well in order for you to vacuum without the lights off you would have to turn them on. Which is what is usually the case anyway. The lights are usually on already. I was just picking on him. What he should of said was vacuum with the lights off.
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