TW201625974A - Motor device capable of simplifying power measurement - Google Patents

Abstract

A motor device capable of simplifying power measurement is disclosed, which comprises: a three-phase motor; a current meter, coupled to a phase power line of the three-phase motor so as to obtain a phase current measurement value; and a power calculation unit, comprising at least one memory for storing a rated phase voltage value and a lookup table of power factors and phase currents, wherein the power calculation unit obtains a power factor from the lookup table according to the phase current measurement value, and obtains a three-phase power by multiplying a product of the phase current measurement value, the rated phase voltage value and the power factor by 3.

Description

Motor device capable of simplifying power measurement

This invention relates to motor devices, and more particularly to a motor device that simplifies power measurement.

Due to the extreme climate, all countries in the world have vigorously promoted energy conservation and carbon reduction. At present, the international standard ISO50001 energy management standard is actively promoting. Among them, electric energy monitoring and recording is an important management project. However, due to the high cost of power management monitoring system construction, Therefore, it was hindered when the factory was implemented. Therefore, if the cost of the electric energy measuring device can be effectively reduced, it will help to promote the power management of the factory, thereby achieving the purpose of saving electricity.

Moreover, in a general factory, a three-phase motor is a common power device, and in power planning, a separate motor drive power is generally supplied to a three-phase motor by a MCC-motor control center. A motor protection device is disposed in the motor control center. Since the motor control center can supply power to a plurality of three-phase motors, to monitor the power consumption of each three-phase motor, a three-phase is added to the connection circuit between the motor control center and each three-phase motor. The electric meter and three CT (current transformer) have high construction cost, which is what needs to be improved.

In order to solve the aforementioned problems, there is a need for a motor device that simplifies power measurement.

It is an object of the present invention to disclose a motor apparatus that simplifies power measurement by simplifying the power measurement procedure of a three-phase motor by a pre-established comparison table of power factor and phase current.

Another object of the present invention is to disclose a motor apparatus that simplifies power measurement, in which only one phase current needs to be measured during operation of a three-phase motor to estimate the three-phase power of the three-phase motor.

In order to achieve the above object, a motor device capable of simplifying power measurement is proposed, which has: a three-phase motor; an ammeter coupled to a phase power line of the three-phase motor to obtain a phase current measurement And a power calculation unit having at least one memory for storing a nominal phase voltage value and a power factor and phase current comparison table, wherein the power calculation unit is based on the phase current measurement value from the power The comparison table of the factor and the phase current obtains a power factor, and a three-phase power is obtained according to the phase current measurement value, the rated phase voltage value, and the power factor multiplied by three times.

In one embodiment, the nominal phase voltage value is a pre-input value.

In an embodiment, the ammeter comprises a current comparator.

In one embodiment, the three phase motor is powered by a motor control center.

The detailed description of the drawings and the preferred embodiments are set forth in the accompanying drawings.

100‧‧‧Three-phase motor

110‧‧‧ galvanometer

120‧‧‧Power calculation unit

200‧‧‧Motor Control Center

Figure 1 depicts a typical motor power factor table.

2 is a block diagram of a preferred embodiment of a motor apparatus for simplifying power measurement according to the present invention.

The principle of the present invention will be described below. According to IEEE Std1459-2000, under the condition that the three-phase is balanced and the voltage is sinusoidal, the three-phase power can be equivalent to 3* phase voltage*phase current*power factor. In the three-phase motor system of the direct drive of the mains, since the motor drive power supply and the three-phase motor are all three-phase balanced, and the power supply is a three-phase balanced sine wave, the three-phase power of the three-phase motor can be calculated according to the above formula. .

In addition, please refer to FIG. 1, which shows a typical motor power factor table. As can be seen from Figure 1, a motor will have different power factors under different load conditions. Moreover, in the general case, the mains voltage can be regarded as a fixed constant. Therefore, when the voltage is fixed, there is a correspondence between the current and the power factor of the motor.

In accordance with the above description, the present invention pre-establishes a comparison table between the phase current and the power factor of a three-phase motor at a nominal phase voltage value. In operation, the present invention measures only the single-phase current, and after obtaining a single-phase current value, obtains a power factor value corresponding to the single-phase current value from the comparison table, and then according to the rated phase voltage value, The single-phase current value, the power factor value, and the power calculation formula estimate the three-phase power of the three-phase motor.

Referring to FIG. 2, a block diagram of a preferred embodiment of a motor device for simplifying power measurement according to the present invention is shown. As shown in FIG. 2, the motor device for simplifying power measurement includes a three-phase motor 100, an ammeter 110, a power calculation unit 120, and a motor control center 200.

The three-phase motor 100 is powered by the motor control center 200, and its three-phase power sources V _φ1 , V _φ2 , and V _φ3 are in a balanced state and have a phase angle of 120 degrees.

The galvanometer 110 is coupled to a phase power line of the three-phase motor 100 to obtain a phase current measurement value I _φ1 . The galvanometer 110 can include a current transformer to measure a large current.

The power calculation unit 120 has at least one memory (not shown) for storing a rated phase voltage value and a power factor and phase current comparison table, wherein the power calculation unit is based on the phase current measurement value I _φ1 A power factor is obtained from the comparison table of the power factor and the phase current, and a three-phase power is obtained according to the phase current measured value I _φ1 , the rated phase voltage value, and the power factor is multiplied by three times.

Since the phase voltage of the three-phase motor 100 can be regarded as fixed during actual operation, we can input a nominal phase voltage value, for example 380 (V), without having to measure it during actual operation.

According to the above technical solution, the present invention can provide the following effects:

1. The motor device of the present invention which simplifies power measurement can simplify the power measurement procedure of a three-phase motor by a pre-established comparison table of power factor and phase current.

2. The motor device of the present invention for simplifying power measurement can measure the three-phase power of the three-phase motor only by measuring one phase current during operation of a three-phase motor, thereby greatly saving the three The measurement cost of the phase motor device.

The disclosure of the present invention is a preferred embodiment. Any change or modification of the present invention originating from the technical idea of the present invention and being easily inferred by those skilled in the art will not deviate from the scope of patent rights of the present invention.

In summary, this case, regardless of its purpose, means and efficacy, is showing its technical characteristics that are different from the conventional ones, and its first invention is practical and practical, and it is also in compliance with the patent requirements of the invention. Pray for the patents at an early date.

100‧‧‧Three-phase motor

110‧‧‧ galvanometer

120‧‧‧Power calculation unit

200‧‧‧Motor Control Center

Claims (4)

A motor device capable of simplifying power measurement, comprising: a three-phase motor; an galvanometer coupled to a phase power line of the three-phase motor to obtain a phase current measurement value; and a power calculation unit, a comparison table having at least one memory for storing a nominal phase voltage value and a power factor and a phase current, wherein the power calculation unit is obtained from the comparison table of the power factor and the phase current according to the phase current measurement value A power factor, and a three-phase power is obtained by three times the product of the phase current measurement value, the rated phase voltage value, and the power factor. A motor device for simplifying power measurement as described in claim 1, wherein the rated phase voltage value is a pre-entered value. A motor device as claimed in claim 1, wherein the galvanometer comprises a current comparator. A motor device for simplifying power measurement as described in claim 1, wherein the three-phase motor is powered by a motor control center.