Digital wattmeter: overview, specifications, types and reviews

A digital wattmeter is an advancedmodification of its analogue predecessor. It serves to measure the power in the network, which should not go beyond limitations. Otherwise, fire and equipment damage may occur. With a constant current, the power factor is calculated by multiplying the voltage by the current with an ammeter and a voltmeter. In the alternating current circuit, special measuring devices are required, to which the wattmeter belongs.

Purpose

Advantageously, digital wattmeters are used inspheres of the electric power industry, mechanical engineering, while repairing electrical devices. In everyday life, these devices are used by specialists in electrical engineering, computer equipment, radio amateurs.

Wattmeter features:

• Testing of electrical circuits or their sections.
• Determine the power of devices.
• Test of electrical installations by type of indicator.
• Monitoring the operation of electrical equipment.
• Accounting for the use of electrical energy.

Kinds

The power is measured based on the voltage and current data. According to the method of measuring and issuing summary information, the devices under consideration are divided into analog and digital wattmeters.

The analogue version has a block of self-recording andshowing the elements. They reveal the active power of a certain section of the chain. The screen of such a device has a graduated scale and an arrow. Divisions of the dial are divided by the values ​​of the power index in watts.

Digital modifications measure the active andreactive power. The display shows information about voltage, current strength, the use of electricity per unit of time. The results of measurements are output to a computer device.

How does it work?

The main principle of the digital wattmeter,the circuit of which is shown above, is the preliminary measurement of voltage and current. For this purpose, a current sensor is connected in series to the consuming device, and a voltage indicator along a parallel circuit. These elements are made of thermistors or their analogs (measuring transformers, thermocouples).

Measured parameters instantly by means ofconverters are fed to the internal microprocessor. The power is measured and the results are displayed on the screen and transferred to external devices.

It is worth noting that electrodynamic deviceshave a wide range of actions, work with both constant and alternating current. Inductive devices are only used for AC circuits.

Digital household wattmeter

Most often in the domestic market inthe segment in question is represented by Chinese-made instruments. Such a device measures the power of different consumers of electricity. To start working, plug it into a standard outlet, and plug into the socket of the household digital wattmeter a consumer plug whose power will be measured.

By such an adaptation it is possible to measure the power of the consumer and calculate the spent money for the used electricity from a particular device.

A similar digital wattmeter is equipped with a built-inA battery that serves to store the measured power. The front panel has several buttons for switching modes, specifying the calculated price, clearing information, switching top and bottom position. The maximum working voltage (230 V), frequency (50 Hz), the measured power (from 0 to 3600 W), the limiting current (16 A) are indicated on the back of the case.

Testing

Consider the operation of a digital wattmeter using the examplehousehold modification. After plugging into the socket, the display shows the time required to measure the power of the consumer. Take as an LED lamp. On the screen when the lamp is off, the indicator 0.4 W (the power of the disconnected consumer) is displayed. When the lamp is turned on, the reading changes by 10.3 W. In the graph, the price is zero, if you do not specify it.

The LED can change the luminescence power. With increasing brightness, the power parameters also increase. When the second mode is activated, two fields (time and kW / hours) are also displayed at the top. Since the device has been running for less than an hour, zeros are indicated in the time field. In the lower part, there is a display of information on how many days a particular consumer was measured.

The following mode: the second field displays the mains voltage and the frequency of the current. The upper part of all modes shows the measurement time. The transition to the next mode is accompanied by an indication of the current in the central part of the screen.

Mode 5 shows the minimum power, andsixth - its maximum rate. The cost of electricity is set manually using the buttons. After setting all the parameters, you can measure and calculate the consumption of any household electrical appliance.

Model CP 8506-120

This digital AC wattmeteris designed to measure the power indicators of the active and reactive circuits in a three-phase AC network. The unit shows the current power at the sensor, flashing the analog signal. The digital screen is divided into four digits, the measurements taken are displayed in the form of numbers, taking into account the transformation ratio.

Characteristics:

• The power factor is 1.
• Dimensions - 12x12x15 cm.
• The figures on the screen (height) are 20 mm.
• The maximum reading range is 9999.
• The error is 0.5.
• The conversion speed is no more than 0.5 seconds.
• Operating temperatures range from +5 to +40 degrees Celsius.
• The body protection class is IP 40.
• Power consumption - 5 Watts.
• The operating frequency is 50 Hz.
• Weight - 1200 g.

Multifunctional device CM 3010

This digital wattmeter is designed for measuring DC and AC parameters. In addition, it can be used to work with less accurate counterparts.

Options:

• The range of measurements is 0.002 - 10 A.
• Measurements of DC / AC indicators - 1-1000 / 1-700 V.
• The frequency interval is 40-5000 Hz.
• The error in DC / AC measurements is 0.1% / 0.1%.
• A similar indicator for the measured frequencies in the range 40-5000 Hz is 0.003%.
• Weight - 1 kg.
• The overall dimensions are 22.5х10х20.5 cm.
• Power consumption - 5 Watts.

D 5085

A universal wattmeter serves to measure power in single-phase AC and DC circuits, as well as control devices with lower accuracy.

Characteristics:

• The dimensions are 20.5x29x13.5 cm.
• Working conditions - the temperature is from +10 to +35 degrees with humidity not higher than 80%.
• The error is 0.2.
• The nominal power factor is 1.0.
• The rated current of the parallel circuit of the device is 5 mA.

LOSENE

This digital wattmeter for batteries, pricewhich starts from 500 rubles, is equipped with a liquid crystal display, provides AB checking in real time, with rates from 0 to 60 V. The device has low power consumption, works with 12, 24, 36, 48 V.

Options:

• The operating voltage is 0-60 V.
• The maximum current strength is 0.01 A.
• Operating current - 7 A.
• The overall dimensions are 84х50х20 mm.
• Sequence of data output - no more than 2 seconds.

Reviews

User feedback on the digital wattmeterAC, the circuit of which is shown below, indicate that multifunctional models are preferable, since they are able to work with direct and alternating current. However, consumers who need to measure the capacity of a refrigerator, a lamp, other household appliances or meter readings are quite happy with the household modification. Its advantages include compactness and ease of use. In workshops or at enterprises, it is recommended to use more accurate variations.

Also, the owners note that the accuracy of the indicationslargely depends on the correct temperature regime. They advise choosing a device in comparison of its future purpose, price and quality characteristics.

Digital wattmeter with own hands

For a homemade device, you can take a ready-made Chinese module such as Pzem-021. It is quite popular among folk craftsmen, since it allows measuring several parameters, namely:

• Current strength.
• Voltage.
• Instant power.
• Final consumption for a certain period.

To buy this element will not be difficult on the radio market or in a specialized online store.

It should be noted that this module has a negative side - it does not read the reactive load. Therefore, to measure the indicators of a device with high reactive power, it will not receivefromI. Nevertheless, most household electric meters measure only the active power, so it's quite possible to check what you pay for in the payment.

As the body of the wattmeter served as a solderingthe box is 100x100 mm in size. It should cut holes on both sides, and insert the purchased module into the cover. At the bottom of the box we adapt the outlet. Wires to the device are connected according to the scheme available on the module case (power is supplied to the central contacts, and the load to the extreme elements). A plug with a cord is attached to the output contacts. The meter is ready.

In conclusion

Wattmeter is an instrument necessary in many spheres,as well as in everyday life. Digital analogues are much more informative and accurate. When choosing a device, take into account its characteristics, as well as the operating range and manufacturer. Chinese modifications are much cheaper, but their quality and accuracy leave much to be desired.