I was wondering if anyone can explain alternating current and alternating voltage polarity as it relates to time. If frequency is 60 Hz then I have 60 cycles a second. If a cycle is half positive and half negative then every 120th of a second I have current reverse and polarity reverse. Can...
I was wondering if customers ever actually use the 208 voltage (Phase to neutral) or is it just a mathematical voltage but not one actually used as a matter of practice? Any help would be appreciated. Voltages are 120/240/208.
peetey
I have a few questions about sychronous motors. I am a Journeyman Meterman by trade and we have some old mechanical meters on our system that use synchronous motors (rotors) as a timing mechanism for demand metering. I know that these are more frequency dependent. I am wondering if I have a...
When we have a garden variety 480 volt ungrounded delta service (secondary side) how is it defined by the NEC or in more technical terms? I want to have it defined technically as to distinguish it from other variations of 480 volt transformer arrangements. I like to be very precise about that...
I have a question about the current that the neutral carries under balanced 120v loads. I do realize that the neutral carries no current when there are 240v loads connected. I am pondering the 120v loads when they are exactly the same on L1 and L2. If I have 15 amps on line one and 15 amps on...
Could someone explain quickly how these work to create a neutral? Are they only tied to a ground? Are these considered to be grounding transformers? Under balance loading is the principle to carry zero current?
--peetey
I need to get some info on summation cts and their application. Is there anyone who has used these type of cts to sum up more than one secondary to one output? I was wondering which one I will need if I have 1000:5 cts in a powerhouse generator environment with coupling capacitors as a voltage...
I have another polarity driven question. Lets say I have a pole mounted ct on a single phase service, it is a standard outdoor primary CT. Now I have a choice of a single bushing or a double bushing pt. I choose the double bushing and now make the primary connections. I jumper down from the...
I have a few questions related to burden. If anyone has any links to burden related info on CT's I would really appreciate it. I have a question about control cable length (#10 copper stranded) and its effect on burden. What is considered too long a length from a burden standpoint? How do...
I have asked a question similar to this one but I need definitive answers if I can get them. Imagine I have a pole with 3 transformers in a delta configuration
(secondaries) and it is a 480v ungrounded ct rated service. This only serves one customer that uses it for three phase power. It...
On our system we use KYZ pulses and transducer values to an RTU to have a double check of load and capacity on our system. I am interested in learning more about transducers, how they function, formulas to convert milliamps to actual load values, etc. We on occasion work with our relay...
I am not familiar with the inner working of an isolation relays' input side. I have not been able to find a diagram or schematic of the circuit so I'll just ask as best I can. I have KYZ coming from a meter and Y & Z are on the input of the relay. The K is taken to a neutral reference from...
I have a question about phone line polarity. I know it is refered to as Tip & Ring, but if I have a green and a red phone wire which is + and which is - for correct polarity? What is the AC voltage for a ring, and how many volts DC are on the lines normally? Do you guys find that some...
I am an electrical meterman by trade but am interested in voltages related to relaying and metering. In somes substations there are 69v taps and 120v taps for metering and relays. If the 69 volt is a phase to neutral voltage am I to asssume that the 120v is a phase to phase voltage. Is it...
If I am using a modified sine wave inverter, which type of rechargeable battery is best to work with this device? Can this inverter damage certain types of batteries or electronic devices? Why doesn't this type on inverter work to charge certain batteries?
--peetey
I have a few questions about Pts. Is the iron core of a Pt electrically common with the baseplate of the Pt? When you check to see that a Pt is good after a fuse has blown, what values are expected as far as continuity and ohmic values on the primary winding and the secondary winding? If I...
Could someone explain to me why sometimes a modified sine wave inverter cannot properly charge up a rechargeable battery deviceor run some devices for that matter?
--peetey
Can someone explain to me in the world of engineering and energy measurement what I2h and V2h mean, how are they calculated, and what their use is? Peetey
I have a question that I have posted at other forums but have gotten no useful answers. I am an electrical Meterman by trade. Occasionally we go to test a meter that is on a building under construction and generally the service is 277\480 4 wire wye with a stepdown dry type transformer that is...
I was wondering, are the large generators that utilities use to generate power, synchronous type? I was wondering how they produce a pure sine wave and don't translate a power factor reflective of a wound motor turned into a generator, say a power factor of 30 degrees leading .8660 PF. When I...
