Questions tagged [ac]

This tag refers to alternating current mains power. It usually applies to voltages with >100V RMS, but can also be used for ex. 24V industrial AC power.

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793 views

What is the right way to wire a power inlet to a switch to a dual-primary transformer?

I have a fused power inlet with a voltage selector (Schaffner FN1394-10-05-11). I want to connect it through a separate DPDT switch to a transformer with dual 115V primary windings, and make ...
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7k views

How to determine the pole number or synchronous speed of an AC motor from its rated RPM?

Trying to to determine the pole number or synchronous speed of the following AC motor from its rated RPM. Here are the details: http://www.vanbodegraven.nl/en/products/ac-motors/asea-mbg-200-m-60-6/ ...
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Speed control on a ceiling fan induction motor

I've managed, through the help of others here on Electronics StackExchange to get a ceiling fan motor running, at least at one speed, and in the right direction. I want to enable 3 speed settings on ...
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110 views

Dc Motor giving ac as well as dc voltage when used as generator

When I rotate the rod or the moving part of motor and probe its output through a multimeter (set on ac measuring) it shows around 0.50 volts. When I set the multimeter on dc measuring, it still shows ...
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1answer
812 views

Leakage current in in-line mains filters

I have an two inline (EMI) filters. One with the rating (as given in datasheet): LEAKAGE CURRENT: EACH LINE TO GROUND A. @ 115 VAC 60Hz............................0.20 mA MAX B. @ 250 VAC 50Hz.........
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2 Capacitor induction motor Humming troubleshooting

I have a single phase cutting SAW , 3 years old , yesterday i was cutting thick material it stalled as usually happens , but when i turn it off and then On again now it doesn't rotate , it just makes ...
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3answers
2k views

Drive LED with 220 VAC [duplicate]

I want to light up an LED with 220 VAC using least components. These two circuits come to mind: R1, R2 will be around 200K - 300K depending upon the brightness that I will need. Not much brightness ...
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1answer
123 views

Is there really current in AC current?

Perhaps a simple question, but from the Wikipedia page, electric current is defined as"...a flow of electric charge. In electric circuits this charge is often carried by moving electrons in a wire." (...
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0answers
57 views

How to verify observe or check the source of AC line noise [duplicate]

I'm using a complicated system which reads pressure measurements and sends to an ADC. I will not go to details of the system because I just noticed a big difference due to different AC mains ...
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4answers
2k views

What is a return line in AC power transmission? Why is it needed?

This diagram shows V vs. t for three-phase power transmission: What is the corresponding I vs. t diagram? Would that diagram help explain what a "return line" is and why it is necessary? (cf. the ...
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2answers
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Why am I getting electric shock from 12V DC Adapter

May be this is a weird question. But I am little curios to know why my 12V DC adapter is giving shock when the circuit is complete. I purchased couple of these 1 AMP 200V AC to 12V DC adapter. ...
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2answers
57 views

Alternatives to Large Transformer or PSU for Driving DC Heater

I have a 3D printer heated bed, instead of 3d printing I want to use it for reflow soldering. The bed is intended to operate at 70c, using 12v or 24v. It can be wired in series or parallel depending ...
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3answers
10k views

Can I control a load of 12v DC with a solid state relay 24-380VAC?

I need to control a load of 12v DC and 30A, Can I control the load with an AC solid-state-relay 24-380v and 40A? If it isn't possible, what should I use? Thanks.
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1answer
95 views

Phase Difference

$$i_1 = sin(wt +45^0) $$ $$ i_2 = -sin(wt +60^0)$$ Question : what is the phase difference dows i1 lead i2 My method 1 ) Eliminate minus sign that is i2 = sin(wt + 60 + 180 ) = sin(wt + 240 ) ...
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Why does my laptop charger beep? [closed]

My laptop charger is a 110-220V AC to 18.5V DC. Of late, or maybe I just heard it now, it makes a beeping noise. The noise is very very low. I have to put my ear to it to hear it. The charger works ...
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2answers
143 views

Protecting a relay/SSR when driving AC window cover motor

I'm having trouble switching an AC motor. Relays spark and glue contacts, and SSRs start to flicker and not pass the full input after a while. The motor has 3 terminals for 230VAC mains. One is ...
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1answer
151 views

Help looking for an 220V AC transformer replacement [closed]

My old Philips MC-M250 stereo transformer has died after a power surge. I can't find spares so I'm looking for some compatible replacement. I found a power board circuit in the service manual. AC is ...
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3answers
2k views

Does audio signal change polarity?

Does analog audio signal change polarity, or only "voltage level"? Example, If I took the audio signal from a phone or computer and connected it to an electro magnet (basically just what a speaker is) ...
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4answers
3k views

Reversing the Direction of An Induction Motor?

I have this motor I salvaged from a dryer, and I'm interested in reversing the direction of spin because it spins in the direction opposite of typical machine threads. The Capacitor is shown at the ...
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3answers
97 views

Why is there ampere listed in DC power adapter?

1.The current of a battery is decided by the resistance of electronics used.(Correct me if I am wrong).So there is no limit to current than can be taken from a battery (Except the time) 2.Is this ...
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3answers
68 views

Adding small AC signal to a DC current using inductive coupling

Is it possible to add a small AC current on to a DC current in a wire using inductive coupling from an external source. Or if there is another way, I want to add AC ripples to a DC current. simulate ...
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5answers
441 views

Why do we use alternating current and not direct current for mains power plugs within a house? [duplicate]

I understand that for transporting electric energy it makes way more sense to have AC. But within my house, I don't think that argument holds any more. Devices I use (roughly ordered by power ...
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1answer
197 views

PCB mount AC input and output [closed]

I’m looking for pcb mount AC power connectors. I’m looking for just the metal connectors to solder to the pcb. I can’t find these anywhere. I will be designing the case around it so i do t need to ...
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1answer
97 views

How to replace an AC/AC power that has 2 outputs

Hi the power adapter for my mixer broke, and I need a new one (Alesis MultiMix 16 USB 2.0). However they don't make them anymore, so I'm looking for an alternate solution. It has two 18V outputs that ...
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2answers
381 views

Is there a real difference between the voltages produced at the negative and positive ranges of the AC sine wave?

This a general electrical question. When reviewing the AC sin wave, we note that the curvature of the wave fluctuates between a positive and negative 180 degree range. Is there a real difference ...