Utility voltage question for the electrical gurus

You could see utility voltage as high as 125 Volts and as low as 110 volts.  Most equipment will operate with no problem in that range.  Higher or Lower you begin to see problems.  Plus or minus 10%  I have measured 130 volts and low end less than 100 volts.

If your AC voltmeter has different ranges, why not just measure the household voltage?  Please do be careful.

RJR posted:

If your AC voltmeter has different ranges, why not just measure the household voltage?  Please do be careful.

Well, first I wanted to check that I was actually thinking about this correctly before verifying my theory. I didn't want to be testing utility power for no reason. I have wired outlets 'hot' before, so I do know my way around household wiring. I just have a healthy respect for the power coming out of my walls. 

George

Is my assumption correct that the PH-180 transformer will put out a higher voltage if the input voltage is higher?

I would guess that Lionel did not design the bricks to cap the voltage since they could be assured the input voltage was within a range and that the brick would be plugged into a controller that would adjust the output.

George

Here in northern VA, I find the voltage to be close to 125.  My understanding is that years ago it was 110, and then gradually crept upward.

I don't know if the PH-180 contains voltage limiting circuitry

I tend to agree with your guess, but would note that bricks are not necessarily used with controllers.  On a DCS layout, one can use a PH-180 to feed a Fixed circuit on the TIU.  I use one on 2 Variable TIU circuits which I have set to Fixed operation.

RJR posted:

Here in northern VA, I find the voltage to be close to 125.  My understanding is that years ago it was 110, and then gradually crept upward.

I don't know if the PH-180 contains voltage limiting circuitry

I tend to agree with your guess, but would note that bricks are not necessarily used with controllers.  On a DCS layout, one can use a PH-180 to feed a Fixed circuit on the TIU.  I use one on 2 Variable TIU circuits which I have set to Fixed operation.

Yes, I use mine the same way, and for the fixed channels as well. I was more referring to the Lionel design assumptions.

Have you ever tested the high end voltage output on your bricks?

George

For most utilities the nominal voltage delivered to a home is 120v +/- 5%.  That means a low of 114 and a high of 125.  However, the voltage should not vary more than 5% from whatever the low voltage is to the high voltage during the course of a day.  So if your low voltage during high load times is 114v, the highest you should see during the night is 120v.  If your high is 125v during low load times, your voltage should not drop below 120v during high load times.  Equipment should all work fine within that range.  There are some areas that may still use an old nominal standard of 114v but that has been outdated for a long time.

Your voltage will vary during the course of a day, especially during high load (air conditioning on a hot day) times.  Your utility uses voltage regulators and possibly on-line capacitors to keep the voltage drop down the line such that your home voltage will be between those parameters as the load on the distribution

line varies.  That can give what appears to be some odd results.  During low load times the home nearest the substation might have 120v and the one at the end of line 119v.  During high load times the voltage at the home closest to the substation could actually increase to 125v in order to keep the voltage at the end of the line at 114v.  

Bottom line, don't over think all this stuff and don't be alarmed if you check it at noon and its different than at 10 PM.

Input at PH-180 plug: 124.9 VAC

Output with no load 19.49 VAC

Both measured with a Fluke meter at 11:54 A.M EDT, today.

Dick Malon posted:

For most utilities the nominal voltage delivered to a home is 120v +/- 5%.  That means a low of 114 and a high of 125.  However, the voltage should not vary more than 5% from whatever the low voltage is to the high voltage during the course of a day.  So if your low voltage during high load times is 114v, the highest you should see during the night is 120v.  If your high is 125v during low load times, your voltage should not drop below 120v during high load times.  Equipment should all work fine within that range.  There are some areas that may still use an old nominal standard of 114v but that has been outdated for a long time.

Your voltage will vary during the course of a day, especially during high load (air conditioning on a hot day) times.  Your utility uses voltage regulators and possibly on-line capacitors to keep the voltage drop down the line such that your home voltage will be between those parameters as the load on the distribution

line varies.  That can give what appears to be some odd results.  During low load times the home nearest the substation might have 120v and the one at the end of line 119v.  During high load times the voltage at the home closest to the substation could actually increase to 125v in order to keep the voltage at the end of the line at 114v.  

Bottom line, don't over think all this stuff and don't be alarmed if you check it at noon and its different than at 10 PM.

Good explanation Dick!

RJR posted:

Input at PH-180 plug: 124.9 VAC

Output with no load 19.49 VAC

Both measured with a Fluke meter at 11:54 A.M EDT, today.

Excellent! That supports my theory. I will test my utility power this weekend. I'm traveling right now. 

It also should be the high end of the range, which is good that the brick is not putting out more than 19.5 volts. 

George 

Which can be hard on bulbs.  My passenger cars I have converted to LEDs with voltage regulators, and as for the incandescents, I'm sure voltage drop keeps them closer to 18.

Consider a “Kill-A-Watt” energy usage monitor, or equivalent product, about $20 to $25. I bought one to use with my home generator but it has been very useful around the house. I leave it plugged in continuously to observe what the line voltage is doing 

George S,

Dick Malon is giving you some seriously good advise, over thinking this stuff can drive you nuts!   

Great advise Dick you must be a hands on Electrical Engineer or a Master Electrician.

Every time I see these kind of Questions, I think fondly of Dale.

PCRR/Dave

Very well put Dick!  Thank you sir!