JPH08223877A - Inverter-driven electric motor - Google Patents

Abstract

PURPOSE: To prevent a current, flowing in a stator winding, from partly flowing into a product main body through a conductive bracket of steel plate or the like, by resin molding the bracket and a stator as an integral unit, or by using the resin-made bracket, so as to insulate the stator from the product main body. CONSTITUTION: In an electric motor constituted on a stator 1, which is a laminate of electromagnetic steel plates, and a rotor 2, the stator 1 and housings 4, 5 are formed by resin molding as an integral unit. In this way, when driven by an inverter with a 10 to 30kHz carrier frequency at an output voltage exceeding 150V to 450V, a winding current of the stator 1 is prevented from partly leaking to a product main body having a fan 10 or the like, without connecting an earth wire, a hazard of electric shock or the like can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a main body of an electric motor such as an indoor fan motor of a packaged air conditioner.

[0002]

2. Description of the Related Art In recent years, electric motors such as fan motors for home appliances are required to have speed control and low vibration / noise.

A conventional electric motor will be described below. FIG. 3 is a sectional view of one side of a conventional steel plate motor for an indoor unit of a packaged air conditioner. 1 is a stator made by winding windings on laminated electromagnetic steel plates, 2 is a rotor, 6 is a bracket made of steel plates, 8 is a ground wire, 9 is a ground wire grounding box, and when the motor voltage exceeds 150V Must be connected to the non-charged metal part of the product body.

In the electric motor configured as described above,
When controlling the rotation speed of the electric motor, a phase control by a triac and a tap method in which the stator winding of the induction motor is divided and used are used.

[0005]

However, with the above-mentioned conventional structure, it is difficult to control the rotational speed more precisely, and in order to realize this, frequency control by an inverter is required. In this inverter, when the carrier frequency is set to a value of 10 kHz or more, the current that flows in the winding that is applied to the stator as leakage current flows to the product body through the steel plate bracket and the ground wire and touches the product. There was a problem in that there was a risk of electric shock.

The present invention solves the above-mentioned conventional problems, and is an inverter drive motor having a carrier frequency of 10 kHz to 30 kHz and an inverter drive motor having a voltage of more than 150 V and 480 V or less.
The purpose is to prevent a part of the electric current flowing in the winding wire provided in the slot of the stator from flowing into the product body through the conductive bracket such as a steel plate.

[0007]

In order to achieve this object, an inverter-driven electric motor of the present invention uses a bracket made of resin as an integral body with a stator of the electric motor or a resin-made bracket which is an insulator. Has a structure in which the product body is insulated from the winding provided on the stator and the stator core which is a conductor.

[0008]

[Operation] With this structure, the windings applied to the stator,
Since the stator core, which is a conductor, and the product body are isolated from each other by the resin, which is an insulator, it is possible to prevent the current flowing through the winding of the electric motor from flowing through the bracket to the product body.

[0009]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a one-sided sectional view of an electric motor according to an embodiment of the present invention. Reference numeral 1 is a stator formed by winding windings on laminated electromagnetic steel plates, 2 is a rotor, and 3 is a resin, which is integrally formed with the stator 1 and housings 4 and 5 made of steel plates.

The housing is not limited to a steel plate, but may be a resin housing or an integrally molded resin.

The operation of the electric motor having the above structure will be described below. When the electric motor is operated by an inverter having a carrier frequency of 10 kHz to 30 kHz, the current flowing in the coil is insulated by the resin, so that it is not necessary to attach the ground. Even if the output voltage exceeds 150V, such as when the voltage is commercial 200V or used overseas, no current leaks to the product body.

Although a fan motor is shown in FIG. 1, the present invention is not limited to a fan motor and can be applied to an electric motor for other purposes.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a one-sided sectional view of an electric motor according to a second embodiment of the present invention. Reference numeral 1 is a stator made by winding windings on laminated electromagnetic steel plates, 2 is a rotor, and 7 is a resin bracket.

The operation of the electric motor having the above configuration is the same as that of the first embodiment.

[0017]

As described above, according to the present invention, the leakage current due to the winding current of the stator does not leak to the product body through the stator iron core, and there is no ground even when the output voltage exceeds 150V and 480V or less. Can insulate the motor body from the product body.

[Brief description of drawings]

FIG. 1 is a side cross-sectional view of an electric motor according to an embodiment of the present invention.

FIG. 2 is a side sectional view of an electric motor according to a second embodiment of the present invention.

FIG. 3 is a one-sided sectional view of a conventional electric motor

[Explanation of symbols]

 1 Stator 2 Rotor 3 Resin 4, 5 Housing 6 Steel plate bracket 7 Resin bracket 8 Ground wire 9 Ground wire ground box 10 Fan

Claims (2)

[Claims] 1. An electric motor which is operated at a carrier frequency of an inverter of 10 kHz to 30 kHz and an output voltage of which exceeds 150 V to 480 V, and which comprises a stator and a rotor, wherein a bracket is integrated with the stator. An inverter-driven electric motor molded as a resin. 2. An electric motor which is operated at a carrier frequency of the inverter of 10 kHz to 30 kHz and an output voltage of which exceeds 150 V to 480 V and which is composed of a stator and a rotor, using a resin bracket. Inverter driven electric motor.