Hi,
Do you know where can I find the specs for the ---
Two-stator watt hour-thermal kv demand meter 60hz type D4A-5K..
This unit is installed at my building and I feel it is not working properly.. I would like to read up on how it works so I know if indeed is is working correctly...
Thanks for your help..
Dq

:confused:

What company manufactures it? Have you tried their website?

Hi,
It is a westinghouse and seems to be about 20 years old.. I have contacting westinghouse along with other companies they referred me to...
Dq
:(

I have asked to have this moved to Electrical and Lighting. You may get a better answer there.

Thank you so much for your help... dogs are great :>)
Dq

Westinghouse stopped making KWH meters completely back in 1990, and the D4 series in 1983, and specs are no longer avalaible.

Many of today meters are by ABB, GE, Sangamo, Itron. Most are now no longer mechanical and are electronic.

They all, at least the mechanical, work the same , with subtle differences.There are pins, bearings, gears, armatures, etc, that all can wear out.


Is this a utility company power meter? This is own by them and their responsibility to maintain, test, and repair. If you suspect the meter is malfunctioning they will be glad to come out and check the meter, most likely replace it with a much newer model.

Being a demand meter, there is a multiplier that is assigned to each metered account based on the connected load, type of load, etc. If there has been changes over the years to the amount of load, or the timing of the load, this will affect the outcome of the reading and the billed amount.

Ideally, with a demand meter, load duty cycling and/or shedding will help manage the usage and keep the demand low.

Demand KW is arrived at by the meter keeping track of the total maximum power used in a period anywhere from 15 min to one half hour, this sets the demand that you will be billed at, along with the KWH.

Lets say you have 50000 watts (50KW) of electric heat that when started all at one, within a 15 min period the demand KW will be very high, and set at 50 KW. Your billing will be at that demand rate. You can lower your demand KW by powering on the 50 KW of heat at intervals, what ever is needed to prevent it all from being powered with in one 15 min period.

So if it is by a utility ask them to come out and replace the meter, and ask them to review your loads, and timing of connecting loads, to be sure the demand rate and multiplier( a function of each meter).


If this is a private or a submeter, you should consult with an electrician to upgrade to something newer,and to help understand how to lower your demand.

Tkrussel I wish I was as cool as you

Thank you so much for your information... the kv rate has doubled and nothing has changed at the building and the power is turned on the same as always.. as a matter of interest we even started turning on power in 15 minute intervals and the kv went up 8 points :>0
Dq

Question??
You say "Lets say you have 50000 watts (50KW) of electric heat that when started all at one, within a 15 min period the demand KW will be very high, and set at 50 KW. Your billing will be at that demand rate. You can lower your demand KW by powering on the 50 KW of heat at intervals, what ever is needed to prevent it all from being powered with in one 15 min period."

But isn't the kv measured by how much is on in one given time? So even if I turn on a bit every 15 minutes when all lights are on, it will still be the same kv usage then if I turned on everything all at once??

I have tried turing on stations every 15-30 minutes and the kv reading went up to 48 kv instead of the 40 that it had been reading...

I have requested a new meter as well as the other tests you suggested.. any other ideas??

Thanks again for your input..
Dq

I did some of this years ago when I was managing a factory. If your heaters are thermostatically controlled, if the first one is still on when you turn the last one on, you still have the same peak demand. It you can leave some of them go until the first one cycles off, it should help. If the meter isn't working right, it will be tough to make a logical plan work.

Our peak came about 2 PM. We trimmed it by moving as much as we could to second and third shifts. Much of our operation ran 24 hours a day, but some smaller things didn't run all the time.

If you have heavy motor loads, you can reduce power usage by installing capacitors. Do you have anybody to advise you on that? Your power company may.

What a demand meter is doing is measuring the largest amount of power used in specific period, that block of time is determined by the utility, typically 15 minutes. So that amount of power is in Kilo-watts, (sorry, but just trying be to clear, you keep using kv, which is kilovolts, don't mean to be picky) sets the demand, of which the utility charges you for.

As Labman is explaining better from an actual customers point of view, is to be familiar with your load and process, and do your best to schedule the power usage to limit the highest amount of power, or try to spread your usage/process over time to keep your demand in any increment of time as low as possible.

I learned this better the hard way myself, by turning on a great deal of load at a customers site in a few minutes for testing purposes. I brought up on line 6-100 HP motors that would not normally be turned on in such a short period. I drove their normal demand of 100 KW up in the range of 250 KW, and I don't remember what the charge per KW was or the total bill, but I certainly heard about it.

As I think about my lesson, that load was motors. Using electric heat as an example is probably not the best to illustrate demand, if all electric heat is needed for a process, turning it on incrementally will not keep demand down, as you point out, the high demand will be set once the electric heat is all on, and if this happens each day, each day should be that same and the demand should be set the very first 15 minute period of each billing cycle..

Electric heat does not have the inrush current motors have. Demand is better kept low when turning on large motors by bringing multiple motors on line one 15 min apart from the next ,because one motor can draw 6-10 times the running load, so if a motor draws 100 amps, the starting current can be 600 amps. Do that with a few motors in a short period you can see how an abnormally high demand can be set, and otherwise prevented by turning them on 15 minutes apart.

You mention "stations" what type of load or process is this?

I hope I helped a bit more.

Thanks so much.. I only run lights right now... a/c in summer months... I have contacted electric company but they are no help :>(
Dq

A firm but polite letter to the utility with a cc to your state's Public Utility Commission usually gets their attention.

Thanks for the input.. the stations I was referring to were just a section of lighting I am turning on at one time...
Dq