Measure Power with Power-Mate

The Power-Mate is a highly accurate plug-in energy meter for measuring the electricity usage of appliances. It is ideal for short-term measurement, such as a few hours or days, or even for longer term measurement.

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Power-Mate    aka PowerMate
Accurate measurement of power usage of mains operated equipment

Measure   Watts - Volts - Amps
Cost  & Cost/Hr,   Cost/Qtr, Cost/Yr       kdf  
Energy
Greenhouse-Gas generation - Run Time

Many organisations are subject to soaring power bills but can't work out why. With the Power-Mate (aka PowerMate) you can take back control through the accurate measurement. It is now also possible to determine the actual running costs of equipment or even identify faulty appliances that are using more power than they should.

In these days of occupational health and safety, safety awareness and litigation re unsafe work-practices, the Power-Mate fills another important role.

Appliance technicians, whether they work on TVs, toasters or instruments and electricians are renown for the dangerous practice of attaching 3 alligator clips to a 3 pin plug in order to place a multimeter into the circuit to check current consumption or applied voltage whilst the unit is running.

With a Power-Mate this is totally unnecessary as these measurements can be safely and simply displayed.

The Power-Mate accurately covers the range of loads from 100mW to 2.4kW, or currents from 1mA to 10 Amps. With the units Max and Min feature, start up and surge currents of electrical items are automatically captured for display.

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Operation
The Power-Mate has several main menu modes;
Instantaneous Volts, Current, Power,
Energy, Cost, Greenhouse Gas and Elapsed Time.
When in these main modes extra information is available from 3 other colour-coded buttons.
Whilst in Volts, Current and Power modes, the maximum and minimum values can be displayed.
When in the Cost, Energy and Greenhouse Gas modes, the hourly, quarterly and yearly amounts can be displayed.

It's last measurement is kept in memory if the unit is disconnected from the power.
When re-connected, it will continue measuring from where it last left off.
To start a new measurement, the memory must be cleared via the menu (using the buttons on the front).

The Power-Mate will accurately measure & calculate to display the following information:

Power: …… Watts/now……. Watts/peak………….. Watts/min
Voltage: .….. Volts/now……..Volts/peak………….. Volts/min
Current: …… Amps/now…….Amps/peak…………. Amps/min
Energy: .…… kWh/actual…… kWh/hour…………… kWh/quarter…………. kWh/year
Cost: ……… Cost/actual…… Cost/hour…………… Cost/quarter………….. Cost/year

Greenhouse Gas: Gas/actual produced…Gas prod./hour….Gas prod./quarter…..Gas prod./year

The Power-Mate does not use batteries; it uses a small amount of power (0.5W) from the outlet it is plugged into.
The Power-Mate has a maximum capacity of 10 Amps or 2.4 kilowatts
Accuracy spec. is 1%, typically accuracy is better than 0.5%.

Power-Mate Functions
Each time the “Mode” key is pressed, the Power-Mate will advance to the next mode. The modes are Power, Cost, Energy, G-Gas, Volts and Amps (CUrr). Extra information is available in each mode by pressing one of the other 3 keys.
When in Power, Volts or Amps modes, the Maximum or Minimum values since the test was started can be displayed.
In the Energy, Cost or G-Gas modes, hourly quarterly or yearly values can be displayed.
The last two modes are “CLEAR?” and “SETUP?”.
When Clear is selected, pressing the “Enter” key clears the totals for time, cost, energy and GGas.
When Setup is selected, pressing the “Enter” key allows entry of the unit cost for energy (cents/kilo-Watt-hour), and the ratio of energy to G-Gas emission (1.2kg per kWh is a commonly accepted value).

Some appliances (such as mobile phone chargers) consume a very small amount of energy.
In the Cost mode it could take many hours before even 1 cent has registered.
When checking low power items, the Power-Mate’s display of cents to four digits is very useful and gives confidence that the Power-Mate is measuring.

When measuring low power items (say less than 5 watts) to calculate quarterly or yearly running cost,
greater accuracy can be achieved by measuring the consumption for 24 hours.
The Cost function will then display the actual cost in dollars and cents to four decimal places.
Multiplying the 24- hour result by either 91 or 364 will yield an accurate cost/qr. or cost/yr.

Power, Energy etc
How do the power utilities charge you for their energy?
Some of quantitiesw involveed with Energy are Volts, Amps, Power, Power factor (the phase angle between the voltage and current waveform), wave distortion ccaused by rectification to DC and switching mode power supplies.
The Power-Mate calculates the power usage thousands of times in each second, and integrates these to achieve very realistic and accurate measurements.
Power-factor is therefore taken into account in the result.
All calculations (per hour/per quarter/per year) are based on historical data and are not just snapshot values.

Energy is the amount of power that flows during a given time.
The Power-Mate displays energy as kilo-Watt-hours, the same units used by electricity utility companies.
The supply voltage for Australian households is 230V AC, although it is commonly referred to using the older term of 240V.

When the power utility produces Energy, a side effect is the production of Greenhouse Gases (G-Gas) which is mainly
Carbon Dioxide (CO2). The ratio of Energy produced to the amount of CO2 gas created varies between different generator fuel sources: Coal, Diesel or Natural Gas. If the ratio of Energy to G-Gas is entered into the Power-Mate, it can display the amount of G-Gas that is created by the energy use of an appliance.
The accepted value of greenhouse gas liberated per kilo-Watt-hour, for a fossil-fuelled electricity generator is 1.2kg per 1kWh.

Other Features of the Power-Mate
When in Volts or Amps (CUrr) mode, the Power-Mate will display the maximum and minimum voltages or currents
recorded whilst in use. Both of these modes are very handy aids for service technicians.
The Voltage max and min feature can be used to determine the quality of voltage from the power outlet; a load does not
need to be connected for this purpose.

Specifications

Watts          
Cost & Cost Hr 
Cost Qtr, Yr  
Energy
G-Gas
Run Time
Volts
Amps

0 – 2,500.0 W
0 – $99.9999
0 – $9999.99
0 – 999.999 kWh
0 – 999.999 kg
99Hr, 59Min, 59Sec
170.0 – 270.0V RMS
00.000 – 10.000A RMS

Accuracy for all ranges is better than 1%, (typical accuracy is below 0.5%)
Note: A higher resolution model is available which will display an extra decimal point for Watts, Volts and Amps.
The higher resolution model can display: 1 tenth of a watt, 1 tenth of a volt and 100 micro-Amps.

Standard Warranty: 12 months.
Failsafe design ensures safety of the operator and appliance at all times, for both 10A and 15A versions

Value Packs with extended warranty & pouch

PM10-P2Y Power-Mate 10A Value Pack,
    includes: Power-Mate 10A, PMP001 grey leather look pouch, and extended 2 year warranty: $325+GST

PM10HD-P2Y Power-Mate 10A Heavy Duty Value Pack,
    includes: Power-Mate 10A Heavy Duty, PMP001 grey leather look pouch, and extended 2 year warranty: $395+GST

PM15-P2Y Power-Mate 15A Value Pack,
    includes: Power-Mate 15A, PMP001 grey leather look pouch, and extended 2 year warranty: $445+GST

Power-Mate units only (standard warranty only, no pouch)

PM10A   Power-Mate 10A: Qty 1-4, each: $269+GST       5/11
        Qty 5+, each: please enquire   
  (Previously known as CCI-1058)

PM10AHD  Power-Mate 10A Heavy Duty:  $314+GST
This is externally the same as the Power-Mate 10A (i.e. the plug is rated to 10A), but the internals of the unit are rated to 15A for short periods.
Measure the Power, Running Cost, Voltage, Current, Energy & Greenhouse Gas emission for all types of mains appliances and electrical equipment rated up to 10A, but also measure short periods of up to 15A.
Failsafe design ensures safety of the operator and appliance at all times, for both 10A and 15A versions
  (Previously known as CCI-1058-HD)

PM15A  Power-Mate 15A: $363+GST
The 15A version has a 15A plug and socket on separate cables from the unit, with wider earth pins.
Hence it is not compatible with standard 10A power points.
  (Previously known as CCI-1062)

Power Mate Lite
Low cost digital power meter

The Power-Mate has been a very popular meter over the years but it is out of the price range of many people. The manufacturer has addressed this problem with the Power-Mate Lite - their new meter aimed specifically at the domestic market.

This new meter features

* a multi line backlit LCD display
* intuitive three-button operation
* simplified menus and
* non-volatile memory, so the meter resumes after a power interruption without loss of data.

As well as instantaneous power, it displays energy used and the cost per hour, quarter and year,
greenhouse gas production and some more technical figures such as power-factor, frequency and VA (volt-amperes).

You can also start and stop (or pause) a measurement period.
The meter also has preset measurement period timer choices of 1, 8, 12, and 24 hours and 2, 5, 7, 14, and 28 days.
Even better, unwanted display screens can be suppressed from view.
The Power-Mate Lite will display up to 10 amps of load, meaning it can measure all common loads in the average home or small office.

Accuracy error for all ranges is better than 2%, (typical accuracy is better than 1%)
Dimensions: 110 x 76 x 25 (without lead)

PML-P-2Y Power-Mate Lite Value Pack,
    includes Power-Mate Lite, soft storage pouch, and 2 year extended warranty:   $159 incl GST

PML10A Power-Mate Lite (standard warranty only):     $142 incl GST       6/11

FAQ - Frequently Asked Questions about Power-Mate

1.) Why does the Power-Mate show a lower power reading than the multiplication of volts and current?

The Power-Mate displays True Power - ie what the electricity company bills you for.

If you wish to know the apparent power (VA), simply multiply the RMS Voltage by the RMS current readings.

For a purely resistive load the results between true and apparent powers should be identical. For a capacitive or inductive load the apparent power will be higher than the real power - because of the phase difference between voltage and current.

To calculate power factor, simply divide the true power by the apparent power. You can also then calculate the phase angle if you wish.

When resistive loads are on the mains, I x E x pf = W (assume E = 240V, I = 10A, power factor pf = 1), therefore W=2400

When reactive loads are present, pf is not equal to one, Irms x Erms = VA (Apparent Power) assume E=240V, I = 20A, VA=4800

BUT we must take Power-Factor into account so although the apparent power is 4.8kW, due to say a pf = 0.5 the true power consumed would be actually half or 2400W, which is the same wattage as the first example with only 10A flowing ie. 240V x 20A x 0.5 = 2400W.

In the second case, the electricity company still has to supply the 20A of current, although 10A of the 20A current is actually consumed by the load, the other 10A is circulating current which is flowing through the energy suppliers conductors, mains transformers etc.

Because this extra current flows to the load and then returns from the load back to the mains supply, the supplier can't charge for extra power as it was not consumed, it was supplied and then partly returned. The energy suppliers hate this because they have to generate the higher current required in the first place, and send extra current through their distribution system, transformers etc causing losses heat & stress etc. but they can't actually charge for it so instead they charge a penalty rate (in other words they find a way to charge you for it !) due to the consumers poor power factor. I understand this does not apply to small domestic consumers yet, but does apply to larger industries.
    Click here for more information on Power Factor.

2.) Why does the Power-Mate show a lower current reading than the specification plate of the appliance?

The specification plate will usually show the maximum current for the appliance, this may occur momentarily only at switch on. For instance my monitor specification plate shows a current rating of 1.5Amps but it uses only around 250mA, or about one sixth of the amount shown during normal use.

3.) Will the Power-Mate work with a 60Hz line frequency ?

The Power-Mate works perfectly well on 50 & 60Hz. The IC that does the Power-Calculations was designed & produced in the USA to work over a wide range of frequencies. Please note though, the Power-Mate is designed primarily for 240V The Power-Mate works fine all the way down to ~ 150V but would need modification for use at 110VAC.

 

4.) Can you please tell me the time it takes for a Power-Mate to read the usage cost of an appliance such as a refrigerator.
Is it immediate or does it have to be left connected for a certain time ?

The Power-Mate should be left connected to a refrigerator (or any timed or thermostatically controlled appliance) for a complete diurnal (24 Hour - or multiple of ) measurement, if you wish to ascertain accurate quarterly or yearly running cost figures.

The fridge cycles on and off, the Power-Mate has no way on knowing in advance how long the fridge will run for, as the ambient temperature, number of times the door is opened, the heat load of items put into the fridge or freezer, the thermostat setting, the efficiency of the cooling system etc all contribute to the total power used.

If the Power-Mate was connected to a fridge during its compressors rest or off state, it would appear as if the fridge cost nothing to run, conversely if the compressor was running when the Power-Mate was first connected, and you checked the quarterly or yearly cost it would indicate a much higher figure than the 24 hour measurement will yield, due to the number of stopped or rest cycles that will occur.

The measurement ideally should be done during winter and again during summer and the results averaged to give a more accurate yearly figure.

From my experience after being connected to a fridge for 6 hours, the results will typically be within 10% of the 24 hour measurement, so estimated quarterly and yearly results may well be accurate enough for your purposes.

5.) I need to measure the total energy consumed by a piece of equipment over a short period of time (in the order of a minute).

The instantaneous power levels vary over that time from a few watts to about 300W, and the energy source being measured is the 240V mains. I would expect to measure something like 0.02kWh in a minute, so we need a resolution well under that. I'm sure your power resolution is adequate, but because of the short time and low power, the energy resolution may not be. What do you think ?
The Power-Mate resolves & displays to 0.0001 kWh in standard form so it should easily meet & exceed your requirements, the kWh is measured/calculated and updated each second. It is good to see an application that initially sounds difficult, but which exploits to some degree the capabilities that the Power-Mate unit was originally designed for.

 

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