Amps vs Voltage Amps

[hooterville75]

Hey all. Question involving Voltage Amps. As you all know I'm in the midst of converting a ATX Power Supply to a Lab Bench Power Supply. Today I found a older slot car track I had in the attic, got the plug out for the track and it is 22 Volts 7 VA (Which I'm assuming from researching Google.com means Voltage Amps). I did some research on VA and see a math equation to figure VA out. I'm no Calculas (actually hated that class in high school lol) and have no clue what this all means.

My simple question is this. How does VA compare to regular Amps ? I need a 12 Volt 5 Amps Power supply to power the Bilge Blower Motor I have. The specs on the power supply for the older slot car track is 22 VDC 7 VA. Will this be suitable and compatible to the 12 V 5 Amps I need to supply this blower motor that I can refrain from converting the ATX power supply ? I realize the 22 VDC is well sufficient but am clueless as to how 7 VA compare or are compatible to 5 Amps. Any help would be greatly appreciated. Thanks in advance.

 

[Dusky]

Volt-ampere is the unit of measure for apparent power whereas ampere is the unit of measure for current. The math to convert them is easy, but the concepts behind it are hard because you need to know the line voltage and the voltage of the power supply.
http://www.rapidtables.com/convert/electric/va-to-amp.htm

 

[steezy]

Only 7 left
http://www.amazon.com/BESTEK-cigarette-converter-Amplifier-refrigerator/dp/B0081CWCHI/ref=sr_1_64?ie=UTF8&qid=1354075315&sr=8-64&keywords=110+ac+to+12v+dc

 

[hooterville75]

Volt-ampere is the unit of measure for apparent power whereas ampere is the unit of measure for current. The math to convert them is easy, but the concepts behind it are hard because you need to know the line voltage and the voltage of the power supply.
http://www.rapidtables.com/convert/electric/va-to-amp.htm

Lol. Thanks man. I was at that site but too many squiggly lines and formulas to know what Im doing lol. I graduated high school in 91 and college in 96. Havent used my math skills since ummmm 97 ;D so I have no clue how to figure the info I need out lol. Basically I need to know how many amps 7 VA is LOL.

 

[Dusky]

Basically I need to know how many amps 7 VA is LOL.

Which you can't calculate without knowing the other information in your system. You're better off buying the converter Steezy linked.

 

[hooterville75]

What other info do you need to determine how many amps 7 VA is ? Im already in elbows to A#)@(#@s with the setup I have. Ive already spent the money on everything I need to convert the ATX power supply which I know is plenty plus some Voltage and Amperage wise to run the blower motor. Im not spending additional money on the Power Supply Steezy showed from Amazon when Ive already spent the money on everything else I need to do the ATX PS. Scott from Elm City Hobbies has tried prior to convince me to get the type of PS that Steezy had suggested but again had I not already spent the money to get the supplies to convert my ATX PS I definitely would get the one shown.

The problem with the Power Supply that Steezy has shown from Amazon is the minimum amperage I need to run the Bilge Blower Motor I have is a minimum of Five Amps. It has to be a constant 5 Amps. The way I understand it, if it drops below 5 Amps it will shut off or short out possibly blow up. The problem with the PS Steezy has shown is its a maximum of 5 Amps. You can link with a fuse but thats not a guarantee that it will stay above 5 Amps. The ATX power supply that Im going to be using is a max of 28 Amps on the 12 Volt rail. Not to mention that Ill have a 5 volt rail as well as a 3.3 volt rail if I choose to hook it up. The 3.3 volt rail is 32 Amps and the 5 volt rail is like 26. I can hook the connections of the blower motor to banana clips and disconnect the ATX power supply from the Spray Booth and use it for other things I may need DC for. So the ATX PS is a way better fit for me in more then one way.

If it werent for all this, Id definitely jump on the other type Steezy has shown in a heartbeat. Actually if I had it to do over again Id have never bought the Bilge Blower Motor and actually had some patience and purchased a Dayton Squirell cage blower motor that ran off AC.

 

[Elm City Hobbies]

Simple...if the blower needs 5 amps to run and the PS puts out 5 amps...then it is going to run.

Think you are way over analyzing it. Everything has a plus or minus percentage for it to run...if for example the PS dropped to 4.5amps, it isn't going to do anything to your blower, other than maybe make it run slightly slower.

If the PS drops amperage suddenly, then you have bigger problems, as in the PS is fried....note I said PS fried, not your blower, meaning if something goes wrong, the PS is going to be the first to go, and all it will do is stop giving power to the blower. Replace the PS and you are good to go.

Those PS are designed to run for many hours, I really don't think you would have a problem with them.

As far as Volt Amps go, it is usually only used in AC circuits, usually in DC circuits it is referred to as Watts (but they are not necessarily the same). Volt Amp is the measurement of the power in the circuit (not # of volts, or # of amps, but power, or potential power of the PS)

Besides which, the slot car PS is 22VDC....which is way too much voltage for your blower motor, and the approx. amperage of the slot car PS is about 3Amps.

Simple calculation:

P=VI

P=Power, in this case 7VA
V=Volts, in this case 22VDC

22 divided by 7, gives you 3.14amps, far too little to run the blower if it requires 5 amps.

 

[hooterville75]

Well alrighty then. Thanks for the clarification and answering my questions. The Power Supply for the slot car track says

120 VAC 0.12 Amps 60 Hz only
22 VDC 7 VA

I can only comprehend what I assume from what was explained to me prior.

 

[Grendels]

Scott got it backwards. It is V divided by VA. So A=7/22, no where near enough to power that blower motor. Not to mention the voltage is far to high.

I wouldn't let any kid near a slot car track that put out 34 amps. Touch the two rails on the track and you have one fried kid. 1 Amp measures 6.214x10^18 electrons per second That many electrons moving through your body per second tears up a lot of chemical bonds. That is how electricity kills......

Remember this: Amperage kills, Voltage does not.

This is why stun guns are 22,000 volts. Voltage is potential energy, which means that you have the possibly to do work. Or in other words, the possibility to move electrons. The big difference between voltage and amperage is that with voltage it uses the available electrons. A power supply or battery is a reservoir of electrons. A wall outlet or car battery can supply a tremendous amount of electrons. While a 9V battery cannot and it is relatively safer. This is why I will NOT mess around with a Computer power supply. It can supply a huge amount of electrons at a good voltage to generate a large current.

With a stun gun, the battery in the gun is used to generate a high voltage. It is not used to supply electrons for current. The electrons that move are provided by your nervous system. The voltage on the stun gun gets the electrons in your body to move in a direction opposite of what your nervous system is designed to handle, so it is like one big miss fire and just scrambles the circuits. These circuits are use to handling electrons so no permanent damage occurs. Just a temporary disruption.

Just keep in mind that 1 amp can kill.

Car batteries typically have 200 Amps and are exceedingly dangerous.....

 

[Elm City Hobbies]

D'OH!

Although I said 3.14 amps, and not 34, still would be a crap load. Did get it backwards though, should be 0.32amps.

120 VAC 0.12 Amps 60 Hz only

This just basically means that what you plug the PS into should only be those parameters, IE: only for use in North America, unless you have a converter. The PS input.

22 VDC 7 VA

This is the PS output if it is plugged into the input above