I've got a Watts-Up meter. That's how I arrived at the numbers in my post on my fridge. Smarthome.com has them for $99.95. I have found them to be quite useful for measuring power consumption in appliances and for my job when troubleshooting!
Help With Math, Calculating Total Amps
- Thread starter Unimatic1140
- Start date
Help Support :
Hi Robert
You just add the amperages.
The formula you are probably thinking of is for resistors in parallel:
total resistance is the reciprocal of the sum of the reciprocals of the individual resistors (in amps).
The reciprocal of a number is one over the number, eg reciprocal of 4 is 1/4.
the reciprocal of a fraction is to turn the fraction upside down, ie the reciprocal of 2/3 is 3/2.
Sorry but I'm not too good at typing this up, but I'll give it a go.
For example:
what is the total resistance of a 2 ohm resistor and a 4 ohm resistor in parallel?
reciprocals of 2 and 4 are 1/2 and 1/4.
add the reciprocals:
1/2 + 1/4 = 2/4 + 1/4 = 3/4
reciprocal of that is the answer:
reciprocal of 3/4 is 4/3 = 1 1/3.
So the answer is 1 1/3 ohms, or 1.33 ohms.
Chris.
You just add the amperages.
The formula you are probably thinking of is for resistors in parallel:
total resistance is the reciprocal of the sum of the reciprocals of the individual resistors (in amps).
The reciprocal of a number is one over the number, eg reciprocal of 4 is 1/4.
the reciprocal of a fraction is to turn the fraction upside down, ie the reciprocal of 2/3 is 3/2.
Sorry but I'm not too good at typing this up, but I'll give it a go.
For example:
what is the total resistance of a 2 ohm resistor and a 4 ohm resistor in parallel?
reciprocals of 2 and 4 are 1/2 and 1/4.
add the reciprocals:
1/2 + 1/4 = 2/4 + 1/4 = 3/4
reciprocal of that is the answer:
reciprocal of 3/4 is 4/3 = 1 1/3.
So the answer is 1 1/3 ohms, or 1.33 ohms.
Chris.
Cool subway page!
This page is filled with THOUSANDS of pictures of the New York subway system, trains, and other lore. There's all sorts of technical information here too, including how the rail system was powered. Back in 1903 when the subway system was installed, there were a multitude of competing electrical companies (Remember Edison's DC, and Westinghouse's AC?) not to mention the fact that some neighborhoods didn't even have electricity yet. The New York subway system had to produce it's own power because of this. They chose 25hz AC just like larger electric trains were using to transmit it around the city, and converted it to DC in rotary converters to power the motors to in the trains. DC was much easier for speed control in multitude of stops of the urban system.
In the days before solid state recitifiers, AC was converted to DC using a device that looked similar to a giant generator, but what it used was a series of brushes that would "turn over" at the same frequency as the AC current, effectively converting it to DC. Take a look at the sub station pictures in the NYC subway.org site!
http://nycsubway.org
This page is filled with THOUSANDS of pictures of the New York subway system, trains, and other lore. There's all sorts of technical information here too, including how the rail system was powered. Back in 1903 when the subway system was installed, there were a multitude of competing electrical companies (Remember Edison's DC, and Westinghouse's AC?) not to mention the fact that some neighborhoods didn't even have electricity yet. The New York subway system had to produce it's own power because of this. They chose 25hz AC just like larger electric trains were using to transmit it around the city, and converted it to DC in rotary converters to power the motors to in the trains. DC was much easier for speed control in multitude of stops of the urban system.
In the days before solid state recitifiers, AC was converted to DC using a device that looked similar to a giant generator, but what it used was a series of brushes that would "turn over" at the same frequency as the AC current, effectively converting it to DC. Take a look at the sub station pictures in the NYC subway.org site!
http://nycsubway.org
another thought
Maybe you are thinking of power factor??
I'm not at all clear on power factor, but it plays around with the amps, meaning that amps in an AC circuit can be less than or more than you would expect.
MY very vague understanding: say a motor is 240 volt 480 watt. You would expect it to draw 2 amps.
(volts x amps = watts)
But the power factor of the motor can influence the amps draw.
I can explain it roughly if anyone would like but it can get a bit drawn out... basically it's to do with the AC volts and AC amps being out of phase, so that the simple equation doesn't work.
It becomes relevant when operating machinery on an inverter or a generator, you need to have a generator capable of more watts than the appliance to be used on it states on the name plate.
Anyway I'm getting out of my depth here...
chris.
Maybe you are thinking of power factor??
I'm not at all clear on power factor, but it plays around with the amps, meaning that amps in an AC circuit can be less than or more than you would expect.
MY very vague understanding: say a motor is 240 volt 480 watt. You would expect it to draw 2 amps.
(volts x amps = watts)
But the power factor of the motor can influence the amps draw.
I can explain it roughly if anyone would like but it can get a bit drawn out... basically it's to do with the AC volts and AC amps being out of phase, so that the simple equation doesn't work.
It becomes relevant when operating machinery on an inverter or a generator, you need to have a generator capable of more watts than the appliance to be used on it states on the name plate.
Anyway I'm getting out of my depth here...
chris.
Yes Robert Gizmo is correct
you just add the amperages together linearly. I was thinking of the resistances in parallel.
( Robert wanted me to post my correction so that everybody would know his hunch was correct ---OY! ThaT Boy!)
I was looking into cycloconverters last year for converting our 60 HZ into 50 HZ, they are big, expensive and ugly! I wanted to ship over a new induction cooktop from Europe BUT NOW I can just go to Sears and slap down my Sears card and BOOM BOOM DONE I've got new Induction.
you just add the amperages together linearly. I was thinking of the resistances in parallel.
( Robert wanted me to post my correction so that everybody would know his hunch was correct ---OY! ThaT Boy!)
I was looking into cycloconverters last year for converting our 60 HZ into 50 HZ, they are big, expensive and ugly! I wanted to ship over a new induction cooktop from Europe BUT NOW I can just go to Sears and slap down my Sears card and BOOM BOOM DONE I've got new Induction.
kenmore1978
Well-known member
- Joined
- Sep 8, 2004
- Messages
- 2,119
AC to DC
"In the days before solid state recitifiers, AC was converted to DC using a device that looked similar to a giant generator, but what it used was a series of brushes that would "turn over" at the same frequency as the AC current, effectively converting it to DC."
That's the device that superseded the MG sets. They were what were refered to as rotary or "synchronus" convertors. These and MG sets were in use in San Francisco to power their streetcar and electric trolleybus system up into the 80's
"In the days before solid state recitifiers, AC was converted to DC using a device that looked similar to a giant generator, but what it used was a series of brushes that would "turn over" at the same frequency as the AC current, effectively converting it to DC."
That's the device that superseded the MG sets. They were what were refered to as rotary or "synchronus" convertors. These and MG sets were in use in San Francisco to power their streetcar and electric trolleybus system up into the 80's
Thanks Jon and everyone! OK now I know that when I'm running the Super Hot Cycle (or what ever I call it) I'll be using:
Unimatic Mechanism Pulsating = 6.5 Amps
Heater = 10.0 Amps
Recirculation Pump = 2.1 Amps
Total Max Amp Draw = 18.6.
Since the washer will be plugged into a 20 amp breaker that should be just fine for the 12 min wash period with occasional recirculating heated-soaks thrown in for another 8 or so minutes at 12.1 amps. The rest of the time will be a much lower AMP draw, as well as when I run warm and cool water cycles.
While the computer to run the washer will be plugged into a different outlet, I'm going to assume that computers probably draw very little amperage.
Unimatic Mechanism Pulsating = 6.5 Amps
Heater = 10.0 Amps
Recirculation Pump = 2.1 Amps
Total Max Amp Draw = 18.6.
Since the washer will be plugged into a 20 amp breaker that should be just fine for the 12 min wash period with occasional recirculating heated-soaks thrown in for another 8 or so minutes at 12.1 amps. The rest of the time will be a much lower AMP draw, as well as when I run warm and cool water cycles.
While the computer to run the washer will be plugged into a different outlet, I'm going to assume that computers probably draw very little amperage.
My Frigemore has a nameplate rating of 12A. I have run it through full cycles with a recording ammeter, and the max run amps would be about 6A with brief 9A surges.
Manufacturers are free to put whatever value they want on a nameplate. According to the National Electrical Code, 12A is the maximum load on a 15A circuit, and any appliance with a nameplate current exceeding 50% of the circuit rating needs a dedicated circuit.
Nameplate current of 12A is manufacturer warranty CYA.
Use a clamp-on ammeter with each machine. Take the highest running amperage of each, add them up, and then add 25% of the highest rating.
Manufacturers are free to put whatever value they want on a nameplate. According to the National Electrical Code, 12A is the maximum load on a 15A circuit, and any appliance with a nameplate current exceeding 50% of the circuit rating needs a dedicated circuit.
Nameplate current of 12A is manufacturer warranty CYA.
Use a clamp-on ammeter with each machine. Take the highest running amperage of each, add them up, and then add 25% of the highest rating.
