Good morning everyone, I am trying to design an AC Power Supply at my job from s

Question

Good morning everyone,

I am trying to design an AC Power Supply at my job from scratch. The purpose of the power supply is to perform an abnormal overvoltage test on a TMOV (Thermally Protected Metal Oxide Varistor) with 2 terminals to see if it will disconnect before burning up. I will have to test each TMOV at 240 Volts at a current level of 0.125, 0.5, 2.5, 5, and 10 amps. I will also be testing at 480 Volts AC at these same current levels. This is my 1st Design project which is why I am asking for some assistance. We are trying to make the power supply in spec according to UL certifications. I am aware that I will need a load for each current level which consists of a voltage source, a series resistor, and a series inductor. A Transformer, heaters, fuse, etc.

http://maxembedded.com/2013/02/how-to-build-your-own-power-supply/

This is the website that I have been referring to for parts that I may need for the experiment. Now that I've explained what I am trying to do I guess my question is has anyone ever built an AC Power Supply in a professional setting and knows first hand what exactly I need to order in order to get this experiment going ? My deadline will be arriving within two weeks in order to present this to my managers. Also below is a link to a book on the UL certifications that are expected of us to have completed for the AC power supply. This is the email that my boss had sent me in regards to what we are trying to achieve:

"Type 4 Component Assemblies. As I explained we need to build a new piece of equipment to perform the Limited Current Abnormal Overvoltage Test (Section 44.4, page 95). Table 44.6 lists the required short circuit currents that we must meet. This section references back to Table 44.1, page 89, which specifies the minimum test voltages that must be applied for a rated nominal AC voltage. We are only concerned with the single phase voltage ratings.

I need you to start designing a tester that can apply the minimum test voltages and the selected short circuit currents. Remember that the standard requires short circuit currents at the minimum voltages listed. We will need to apply up to 1000VAC."

Thank You

file:///C:/Users/Blaine/AppData/Local/Microsoft/Windows/INetCache/Content.Outlook/BF7MHM8M/4th%20Edition%20-%20UL1449%20-%2008-28-2016%20(2).pdf

Idk if this link will post because it is registered under my documents but if you would like to see the book in order to refer to the email that my boss has sent me let me know and I can email you the pictures of the pages that he is referring to so that you can see a clear picture of what is happening.

Well thank you very much and I will appreciate all of the help that I can get.

Explanation / Answer

Resistors ¼ watt +-5%
R1, R5————22K
R2, R3————100K
R4—————–1K
R6—————–22K
R7—————–47K
R8—————–39K
R9—————–100 ohm 10 W
VR1—–Variable Resistors 50K
VR2—–Potentiometer (B) 2K
VR3—–Variable Resistors 4.7K
VR4——Potentiometer 1M
Capacitors
C1————220uF 100V Electrolytic
C2————0.33uF 50V Mylar
C3————0.01uF 50V Mylar
C4————10uF 63V Electrolytic
Semiconductors
BD1– Bridge Rectifier___220V 6 Amp_______ = 1 pcs.
D1, D2, D3———1N4001 ___1A 50V Diode__ = 3 pcs.
IC1——————-TLC272 ______________ = 1 pcs.
IC2——————-H11D2 _______________= 1 pcs.
IC3——————-LM7812 __12V regulator IC___= 1 pcs.
LED1—————-LED as you need. ___ = 1 pcs.
Q1——————–BC550B ________ = 1 pcs.
Q2——————–BC141 _________ = 1 pcs.
Q3, Q4—————BD241C ________ = 2 pcs.
ZD1—-Zener Diode__33V 1W _______= 1 pcs.
Others
F1——-Fuse 1 Amp_______________ = 1 pcs.
F2——-Fuse 2 Amp_______________ = 1 pcs.
M1——Meter 100 uA______________ = 1 pcs.
T1——-Transformer Pri: 220 volts ; Sec: 36 volts 3 Amp___1 pcs.

How to builds
We need to provides all components as list above. Then make PCB as Figure 4 an actual-size of Single-sided Copper PCB layout. And Component layout for the PCB.

Note: This project have a lot of parts and high current, You need to have enough electronic experience.
Q1, Q3 and IC3 need to use heatsink. And importance Q4-BD241C must mounted large heatsink size.

Testing and tuning
Check the accuracy of the circuit again to make sure, before you experimental to enter input voltage. If a short circuit will damage the machine. Adjust VR2 is used to adjust the voltage to the lowest position. To connects AC 36 volts from transformer to input. Then use the meter to measure the voltage of the output switch. Pressure must not exceed 0.5 volts. If too much, to hurry off. And check the equipment again.

When sure that everything is normal, adjust to next step,VR2 were adjusted to increase or decrease the output voltage switch, to adjust minimum of 0.5 volts and a maximum of 30 volts.

Next, adjust the meter is used to switch the output voltage can be read correctly. To change the scale of the meter before 100 micro amps to 30 volts. Then start adjusting the meter by adjusting VR4 to the highest position, set the multimeter to measure AC voltage at the output.

Then turn it on, adjust VR1 to the minimum resistance, adjust VR1 to the top position. VR3 adjusts the output meter reads 30 volts without having to do the voltage shown on the meter of the machine.

Then adjust VR1 VR2 to adjust the minimum position potentiometer output voltage is 0 volts.
Then adjust VR2 to the top position again. The voltage reading is 30 volts. Then adjust VR4 for the meter reading on the meter is connected directly to the output. shall be available

Application
We can apply the work to be associated with voltage switch it. Which may be used in place of a transformer Or used as a power source in the experimental circuit on AC power.

Caution is not the output short circuit. This will result in very high current flows through transistor transistor Q3 will make this waste.

When not in use, turn off the machine. Because within the 100 ohm load at all times to cycle to work. Therefore, the consumption of electric power to the load in vain.

We may be used to connect an external diode bridge another time. To change AC voltage to DC power. Gives us the power source for both AC and DC power to operate simultaneously

use high voltage capacitors.

hope i was of help. thats it how much i can say for your query

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