Questions tagged [ac]
The ac tag has no usage guidance.
26 questions
1
vote
2
answers
44
views
Photovoltaic system with storage in a shed 50 m from my home. Where to put inverter and batteries?
I want to install a photovoltaic system in a shelter in my garden, because it has a very good south exposition (my house is not south and shaded by high trees) and a reasonable surface (20 m2).
I am ...
- 56
0
votes
0
answers
35
views
Getting the actual CFM and kW from AC current
I have this AHU with a 3-phase induction motor which is connected to a VFD. I get continuous frequency data from the VFD and I would like to know the CFM output and energy consumption in kW at each ...
1
vote
3
answers
581
views
Single hose portable air conditioner with door open?
I have a strange question/theory that I'd like some advice on.
I currently have a garden shed that is being used as a home office. On sunny days, the inside of the shed gets very hot - too hot for me ...
- 11
0
votes
3
answers
306
views
Why are my water pumps becoming noisy all of a sudden
I purchased 3 identical submersible water pumps for my irrigation mister heads.
Im running them in clear tap water at room temperature(blockages are not a concern)
After running one for 30 hours, the ...
0
votes
0
answers
24
views
Convert a 3 poles AC/DC battery charger into a 2 poles DC power supply?
I have a battery charger with a positive pole, a negative pole and a common pole, see the below diagram.
The output voltage is as follows:
positive-common 5V DC
negative-common 5V DC
positive-...
- 101
0
votes
1
answer
123
views
Basic questions about power grid stability with variable loads and sources
I am curious about integration of renewable energy in electricity grids. I am a mechanical engineer and understand energy and power but I have little knowledge about electricity. I will be thankful if ...
- 148
1
vote
0
answers
40
views
Household 3 phase devices
So, I'm not sure if this is the right place to ask this, but have been working on modifying a lawn mower robot that has, for roughly 3 years now been stored under less than favorable conditions. As a ...
- 265
0
votes
3
answers
805
views
AC/DC Laptop adapter power losses
I have a laptop power adapter shown in the picture below.
It is written there
170Watt
INPUT: 100-240V ~ 2.5A
OUTPUT: 20V 8.5A
I believe for AC Input they mean Root mean square voltage/current.
for ...
- 115
0
votes
1
answer
743
views
Are AC generators more efficient than DC generators?
I've been doing some research into AC and DC generators, and I was wondering if AC has any advantages in terms of efficiency.
Given that AC generators are usually brushless while DC generators ...
- 11
3
votes
1
answer
566
views
Arduino DAC to Speaker
I'm working with an Arduino Due's two DAC pins.
I want to output to a single 4W 5.7Ohm speaker to test my code, with the intent of eventually outputting to a set of speakers (woofer, mid-range, and ...
1
vote
1
answer
48
views
Design of a hydrogen and corrosion sensor query
I’m designing a hydrogen and corrosion sensor. A thin film changes resistance based on hydrogen concentration. Then the capacitance between two electrodes will change depending on substrate thickness (...
- 11
3
votes
0
answers
58
views
Understanding transformer secondary winding
I purchased a step down transformer from a junk yard. I tested the transformer and it works but I am confused as to the secondary winding.
The primary side has these markings
G 0V 100V
The secondary ...
- 43
0
votes
0
answers
39
views
Issues with Building AC Generator
So we are trying to build an AC generator, an alternator, if you will. We are using a 5" PVC pipe for the body with a hole drilled diametrically, through which a bolt passes. Inside of this pipe, on ...
user14362
1
vote
1
answer
314
views
Calculate amount of evaporative coolers needed to cool down an area
I have a task to create a software that calculates how much evaporative coolers are needed to maintain a certain temperature in a given room. I need to create a simple form, where variables are next :
...
- 13
2
votes
0
answers
43
views
Breakdown voltage of electronic devices
Diode and transistor have reverse breakdown voltage. Are these devices permanently destroyed under such voltage? Also, do these devices have breakdown voltage when AC voltage is applied? How much AC ...
- 21
-2
votes
1
answer
74
views
Which Generator is "Better": DC or AC? [closed]
So, I have a project where I have a bicycle that powers a type of generator. I have everything else done, but I need to pick a generator.
My first problem is that I don't really know which type of ...
2
votes
1
answer
50
views
Are there any variable frequency drives that work digitally?
By this I mean can any DC to AC variable frequency drives invert digitally (no moving parts) and if so how do these work? Is this possible for both sine and square wave inverters?
- 240
2
votes
0
answers
307
views
What is the maximum frequency of an AC current?
I saw that the rpm of a synchronous motor is proportional to the frequency of current alteration and I was wondering if there is a theoretical maximum frequency (regardless of magnet strength)? Also ...
- 240
0
votes
3
answers
93
views
Increasing speed and efficiency of ac induction motor
If you wanted highest efficientcy and speed from an AC motor what would you do?
Could the rate of alternation of current be optimizes?
More windings?
Materials?
More lamination?
Other factors I haven'...
- 240
2
votes
1
answer
388
views
Mechanically increasing RPM of ac induction motor
If you spin the stator of an AC induction motor than would the rotation of the rotor increase? Or would it have a different affect such as moving with a higher force?
- 240
0
votes
1
answer
62
views
AC induction motor
Could the rotor be shaped like a fan inside the stator of an AC induction motor. And could the stator act as a duct.
Would this lead to a high airflow:materials used.
Thanks
- 240
8
votes
1
answer
2k
views
Is a 3 Hz beat frequency from my neighbor's HVAC a sign of a malfunction?
I'm being annoyed by a pulsating hum which comes from my neighbor's HVAC system. I read up a little on the design of HVAC systems and I came to a tentative conclusion that what I'm hearing is a ...
- 183
-3
votes
1
answer
1k
views
How to convert VDC to VAC at a high frequency? [closed]
How to convert 10 VDC to VAC at a high frequency, say 10 MHz? VACpp can be +-10V or +-5V.
- 1
1
vote
1
answer
91
views
Will AC Motor Maintain Speed of Descending Object
Suppose we have an AC motor which needs to lower an object at a set speed. We use a PID loop to determine and correct positional errors. Presumably the PID loop will keep the current low as most of ...
- 137
2
votes
4
answers
3k
views
How does single-phase AC synchronous motor work?
In a recent question of mine about microwave plates, jpa correctly identified the type of motor used for microwave plates as a specific variant of AC synchronous motor, equipped with gears that reduce ...
- 6,115
10
votes
4
answers
21k
views
Does a transformer use power when output isn't under load?
I was reading about how AC to DC converters work with a step-down transformer and then a diode bridge to convert the lower, stepped down AC voltage into DC. What I don't understand is since the input ...
- 5,970