Compare the AC coil of the relay with the DC coil

[@jenko701]

Great video , it's a good way to lead into why inductive loads like transformers /motors are rated in Volt amps ,and the subject of power factor .

[@tomluque]

Resistance in AC circuits is known as impedance (Xr) and the impedance is greatly effected by the frequency. The higher the freq. the higher the resistive impedance will be. AC stands for Alternating Current, which causes the current to flow positive and negative. A sign wave that goes between positive to zero or only zero to negative volts will have current always flowing in one direction, which makes this a pulsating DC current and Voltage. The AC relay coil's impedance at 60Hz will be higher than the resistance in this video to achieve a 0.3A reading. Nice video to start the thinking of what is happening.

[@kdog323]

Great video GFM! I was told though to get a better reading of the amp draw (or at least a more accurate one) to wrap the low resistance wire around the amp meter claw and divide the reading by the number of turns.

[@grayfurnaceman]

In my opinion, the 10x wrap is no longer necessary. This was done when everyone had analog meters and they were not accurate in the low amperages. The digital meters are much more accurate. I have video coming out on a comparison of the 2 methods. It should be published the first of Feb. Thanks for the thoughts. GFM

[@TechnicalLee]

It's always good to remember that your DMM measures the DC resistance of a circuit only, which can be very different than AC resistance with inductive loads like coils and motors running at frequency.

[@grayfurnaceman]

Absolutely right.On AC coils, its all about induction. Thanks for the thoughts. GFM

[@provatroy8785]

Reactance has to be added with resistance by vector rule

[@HVACShopTalk]

Fantastic. I look forward to more videos on this subject.

[@themagicman1441]

The inductive reactance of the AC coil drives up the impedance which intern regulates the current in the AC coil. Whereas in the DC coil there is no relative motion of magnetic flux and therefore the only impedance acting on the DC voltage is the resistance of the coil itself. In essence the AC coil creates its own resistance that regulates current where is the DC coil needs to have a set resistance so it does not burn out on the same voltage

[@mshippe61]

You are correct, the math is not even close. I enjoy your videos they are always inforrmative. Thank You

[@alec4672]

So what happenes if I try to power a 24vac relay with 24vdc if I added something to limit the current?

[@henryrobinson9837]

i liked the video, it answered a lit of questions for me

[@shodhanshetty3906]

Which consumes more current AC or DC? Im planning to use solenoid valve for my project. I'm confused between 12V DC and 230V AC. Which will consume less power?

[@grayfurnaceman]

A well designed solenoid will consume about the same power regardless of voltage, DC or AC. GFM

[@kendallriebel3515]

Not to be kinda negative but they were 25.9 on the meters which comes out spot on for the DC side

[@StephenTrenewablenergy]

Like your videos. Just on the coils, dc contacts have to brake huge arc vs ac just to let you inform your viewers.

[@sbitschy]

How come everytime I have trouble finding info on gas related equipment I end up on your videos? Very rhetorical. You do an amazing job. Your videos have helped me so much in my career. Do you use patreon or sell any merchandise that I could buy to support your channel and website?

[@grayfurnaceman]

I appreciate your support. So far I have not decided on merchandise, etc. GFM

[@1986pistolpete]

Same exact meters I keep in my toolbag..Do you work on steam boilers?

[@grayfurnaceman]

Not often. That was my father's bailiwick. GFM

[@bigstuff52]

They must do something to an AC coil to keep it pulled in. One would think that as the current running through the coil is oscillating in strength (sine wave) the armature would chatter-thanks -good vid

[@grayfurnaceman]

john james I'm sure they do. That's kind of a manufacturer thing. GFM

[@kenney5454]

Thanks GFM

[@mrutyunjaysahoo4308]

Useful video

[@grayfurnaceman]

Thanks for the support. GFM

[@josepeixoto3384]

Did not explain much; AC calculations for the coil are MIA!!

[@grayfurnaceman]

It is not an engineering video. It is made for service techs. GFM

[@jerrelvaneiten6526]

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