Basic Electricity

Alan(CaliforniaRadiant)Forbes

I'm OK with line voltage (110v.) and know how to use a meter to find hot and neutral, but I still have a problem with 24 volts.

I was installing a new ignition control board on a Hydropulse boiler and the instructions said to make sure one side of the 24 volt transformer in the boiler was grounded. Well hell, how do I figure out which side of the transformer to ground?

I just had a chance to talk to a retired electrical engineer on a job and asked him the question. He told me that either side can be grounded.

Any further suggestions to help clear this up in my mind?

Best wishes,

Alan

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bigugh_4

Useing your meter

touch only one of the Xfmrs leads , touch the other to anymmajor part of the boiler. If it reads 24 v. the lead or screw your touching on the x fmr is the "hot lead" If it reads zero it is the 'grounded lead.

Wayne_12

transformer ground

Check each terminal of your transformer in relation to the chassis. Place 1 lead of your meter on the terminal and one on the transformer frame. The terminal with 24 volts (actual reading may be as high as 28 volts) potential is the hot terminal or "R" terminal. The terminal with 0 (zero) volts potential is the ground terminal. Many transformers have an internal ground lead.

If you have a reading of infinity on both terminals to ground then the transformer does not have a terminal wired to the chassis. In this case, then either terminal can be wired to a grounding terminal

bigugh_4

ignition systems on

these things use the flame establishment as a switch to st off the ignition system when the pilot flame establishes itself. One side had to be "grounded' such that the little current through the flame can shut off the igniton system. Across the Xfme terminals 24 v is registered. One side must go to ground (the major part of the heating unit it is on) the other wire goes to the power side of the circuit board. both wires may connect to the board, in which case it is usually 'grounded' in side the board when you install it. In your particluar case, just do as I said above. You should be fine with that.

jerry_2

grounding the secondary

Alan,

It's a coin toss whether the transformer you have already has an internal ground. Since they tell you to do it, that may pitch it toward not. Two ways to test.

If the system is not electrified, you can do a resistance test from each lead to the transformer chassis (and make sure you scratch through any insulation coating.) One will be a short if it's grounded.

If the transformer is hot, then you can use AC volt test to see whether either leg shows 0 voltage relative to system ground. If it does, then it's grounded. If they aren't, you'll probably see the meter give a strange reading that has nothing to do with 0 or 24-28V.

If you are sure that the secondary is not grounded, then you pick the one to ground. AC is wonderful that way, as long as you're consistent it works. If you cross them, then you get to find out what is going to do an impression of a cheap lightbulb.

I'm local if you want to give me a call or drop a line.

jerry

Rob Garcha

Basic Elactricity

To make it real easy (I'm a former HydroTherm Rep) If you are changing from the white ign. control (GC-4), to the new black ign. control (GC-4A), splice into the yellow wire running to the gas valve and run it to ground on the chassis of the boiler. The new ignition mod was supposed to be grounded by the screws that mount it,---but it didn't work out that way.. Call me if you have any problems. 703-928-9787.
Rob

Paul Rohrs

under the Basic Electricity \"umbrella\"..................

Since the 'Basic Electricity' question has been posed, can I ask about "Phase"?

I am fairly well versed in hydronic controls, and have Carol Fey's books, but I have not yet grasped "Phase" and the working relationship between motors, water heater elements, etc.

Thanks in advance,

PR

Mike T., Swampeast MO

Phase

I'll try.

It is a relative term as it only has importance when comparing MULTIPLE alternating currents.

Multiple A/C currents are "in phase" when they are positive at the EXACT same time and negative at the EXACT same time. They are "out of phase" in any other condition.

If a simple DC motor is connected to simple alternating current it will just sit and quivver--never turn.

By phasing the current (using/creating another source out of phase with the first) you induce a natural "twist" that gets things turning.

ALL A/C motors utilize multiple phases--some create them (virtually every motor in our house), and others utilize generated multiple phases (commercial/industrial with 3 or more phase motors).

Try to envision the rolling water currents at the bottom of a waterfall--that's how Tesla did it and how he harnessed Niagara falls. Remember--he invented every* type of motor/generator still in use today and his designs were so perfect that only improvements in materials matter.

* Maybe not stepper motors as in your VCR, computer disk drives, CD player but these amount to electronically controlled synchronous (clock) motors that he DID invent. When Bell Laboratories tried to patent the basic "gates" of logic--AND-OR-NOR--they were denied as already invented by Tesla for his remote control AND "scrambing" of such circuitry.

jerry_2

another look at phase

Pardon me, I was trained as a physicist (swatted with rolled newspaper...) and so I actually see this stuff.

throw two stones in the water at the same time and each will create waves. When the waves cross each other, they seem to pass right through each other and keep on going. In some cases you have two crests come together and the wave is twice as high, sometimes two troughs come together and it's twice as low, and other times you have a crest and trough come together and there is no wave at that spot at that time. The relation of the peaks and troughs is called the phase, an it's a circular relation. You only see the up's and downs, so that's why it's a sine wave.

When you generate electricity, you always start with something going in a circle (chipmunks on up.) The way you generate electricity is to move one magnet past another. If you only had one moving magnet and one fixed magnet, you can see the single circle, this is one phase. If you look at the electrons moving in the wire, they go back and forth. People figured out pretty quickly that big motors have a problem with a single phase system, there are dead spots they wont start at, and they are less efficient as well. What's the minimum number of phases without a dead spot (if you got to 4 you didn't get it.) If you forget the lectrons and see the generator, you can see how the phases work. The motor is the reverse.

There are a whole bunch of details, but I hope that gives the overall flavor of what's going on.

jerry