Good afternoon everyone,
I am trying to design an AC Power Supply at my job. 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 standards. I am aware that I will need a load for each current level which consists of a voltage source, a series resistor, and a Variable resistor in some of them. A Transformer, heaters, fuse, etc.
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 a few days 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:
Per our discussion I have attached a copy of the UL1449 standard. The TMOV and SPD devices that we are interested in are considered 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.
Attached to this email besides the PDF file of the UL standards is a picture of what our current AC Power supply looks like now.
Pretty much the summary of all of this would be what are all the components that I need to build this AC power supply ?, what capacity would I need for each item such as the uF for the capacitors, and the Ohms for the resistors etc, and how would this look in a schematic ? Like I said earlier I know that this is a lot I understand but I haven't been getting much help with it at work or from other sites. I appreciate anyone with the knowledge willing to share.
Moderator's note: The UL standard was deleted because it is copyrighted material assigned for the use of one specific individual.
I am trying to design an AC Power Supply at my job. 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 standards. I am aware that I will need a load for each current level which consists of a voltage source, a series resistor, and a Variable resistor in some of them. A Transformer, heaters, fuse, etc.
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 a few days 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:
Per our discussion I have attached a copy of the UL1449 standard. The TMOV and SPD devices that we are interested in are considered 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.
Attached to this email besides the PDF file of the UL standards is a picture of what our current AC Power supply looks like now.
Pretty much the summary of all of this would be what are all the components that I need to build this AC power supply ?, what capacity would I need for each item such as the uF for the capacitors, and the Ohms for the resistors etc, and how would this look in a schematic ? Like I said earlier I know that this is a lot I understand but I haven't been getting much help with it at work or from other sites. I appreciate anyone with the knowledge willing to share.
Moderator's note: The UL standard was deleted because it is copyrighted material assigned for the use of one specific individual.
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