GB2122430A

GB2122430A - Electrical relay and terminal unit of a compressor

Info

Publication number: GB2122430A
Application number: GB08310788A
Authority: GB
Inventors: Alfredo Bar
Original assignee: Necchi SpA
Current assignee: Necchi SpA
Priority date: 1982-06-11
Filing date: 1983-04-21
Publication date: 1984-01-11
Also published as: IT1159282B; SE456300B; DE3320391A1; SE8303313L; IT8242911A0; CA1206245A; IT8242911A1; GB8310788D0; SE8303313D0; GB2122430B

Abstract

A starting and thermal protection relay-terminal box unit (22) for a sealed motor compressor, contains the two relays (28, 40) each in a separate compartment in the same housing, with the housing being mounted on an external wall of the compressor casing so as to be easily accessible to an operator. Included in the unit is a terminal box for electrical connections (46, 48). The unit has a very restricted dimension in the direction outward from the compressor casing. Relay (28) is for thermal protection; relay (40) is a starter relay. <IMAGE>

Description

SPECIFICATION Electrical relay and terminal unit of a compressor The present invention relates to a hermetically sealed motor-driven compressor provided with an electrical relay and terminal unit, especially a unitfor housing starting and thermal protection relays.

In the specification of Italian patent application No.

42916A/81 (GB 2 106 334A)thereisdisclosedastarting relay/terminal box unit, of the positive tempera turecoefficient resistortype, placed on an external wall of the casing shell of a motor-compressor and having such a shape as to have a restricted height relative to the external surface ofthe shell, the connection terminals to a currentfeed line to the unit being arranged to face an operator behind a cooling cabinet containing the compressor.

Itwould be desirable for a starting relay/terminal box unit to additionally be able to house a thermal protection relay arranged close to the starting relay in such a way thatthe relays do not thermally influence each otheryetthe unit has compact dimensions and retains the advantages of the known unit.

According to the present invention there is provided a hermetically sealed motor-driven compressor pro videdwith an electrical relay and terminal unit comprising a substantially box-shaped housing mounted on the external surface of an uprightwall portion of a casing ofthecompressor,wall means being arranged in the housing to separate a space therein for a starting relayfrom a space therein four a thermal protection relay, and an electrical connection terminal box arranged at an external wall of the housingforelectrical connections to the compressor motor, the unit having a restricted transverse dimension in a direction outwardly from said wall portion of the casing.

In a preferred embodiment, the relay and terminal unit comprises a box-shaped outer housing fixed to the external surface ofthe casing shell ofthe motor compressorand insidethe housing there are spaces, adjacent one another, for the starting and thermal protection relays, the spaces being separated by suitable walls. Arranged on a wall ofthe housing is a terminal boxofthecompressor,facing an operator behind a cooling cabinet containing the compressor, the unit having a restricted transverse dimension relative to the external vertical wall of the casing shell.

Embodiments ofthe present invention will now be more paticularly described by way of example with reference to the accompanying drawings, in which: Fig. lisa schematic end view of a relay/terminal box unit mounted on the casing shell of a first motor compressor embodying the invention; Fig. 2 is a view of part ofthe relays/terminal box unit; Fig. 3 is a cross-sectional view along the line 3-3 of Fig. 2; Fig. 4 is a schematic circuit diagram of the unit; Fig. 5 is a front view of a relay/terminal box unit on the casing shell of a second motor compressor embodying the invention; and Fig. 6 is a plan view of the unit of Fig. 5.

Referring nowto the drawings, there is shown in Fig. 1 a casing shell 10 of a hermetically sealed compressor which is mounted by means of plate 12 connected to the shell and a resilient support 14 on the bottom surface 16 of a compartment 18 atthe back of a lower portion 20 of a cooling cabinet of, for example, refrigerating or cooling apparatus.

Fixed laterally to the shell 10its a starting and thermal protection relays/terminal box unit 22, which is closed in the front portion by a cover 24.

The unit 22 is connected to a mains network by means of cables 26.

With reference to Fig. 4, the electrical feed circuit of the motor compressor is formed by a thermal protection relay 28 provided with a bimetallic blade 30 and, according to the type used, a heating resisance 32 having a function which will be described later. The relay 28 is connected in circuit with two windings of an electric motor 34, more particularly with a working winding 36 and a starting winding 38. Connected in series with the starting winding 38 is a starting relay 40 of the positive temperature coefficient resisitor (PTCR) type.

With reference to Fig. 2, the unit 22 comprises an outer housing 43 of plastics material, inside which, in suitable housing spaces separated by walls, are arranged the starting relay 40 and the thermal protection relay 28. Arranged on an outer lateral wall 42 ofthe housing 43 isa terminal box 44 comprising screwterminals 46 and "FASTON" (Trade Mark) spade connectors 48 for electrical connections to the circuit of Fig. 4.

As shown in Figs. 1 and 3, the space occupied bythe unit 22, taken along a line perpendicularto the vertical wall of the shell 10 as represented by H in Fig. 1, is very restricted. The dimension of the unit 22 is thus very reduced in thetransverse direction.

Afurther advantage is that by arranging the terminal box 44 on an external wall of the housing 43 so thatthe terminals 46,48 face an operator behind the cover 24, it is easierforthe operatorto connect the mains network cables to the terminal box and to carry out servicing.

In Figs.5and 6there isshown anotherembodiment, in which another type ofthermal protection relay 50 is employed. The othercomponents shown in Figs. 5 and 6 are otherwise designated bythe same numerals used in Figs. 2 and 3. The relay 50 is of a type commonly used in the motor compressorfield, by contrast with the relay 28 which is produced by Sylvania and sold on the market underthe denomination "glass case protector". It is provided with the heating resistance 32, which has the task of increasing amperometric sensitivity ofthe protector so as to increase the timeforclosing.

1. Ahermeticallysealed motor-driven compressor provided with an electrical relay and terminal unit comprising a substantially box-shaped housing mounted on the external surface of an upright wall portion of a casing ofthe compressor, wall means being arranged in the housing to separate a space therein for a starting relay from a space therein for a thermal protection relay, and an electrical connection terminal box arranged at an external wall of the housing for electrical connections to the compressor motor, the unit having a restricted transverse dimen

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Electrical relay and terminal unit of a compressor The present invention relates to a hermetically sealed motor-driven compressor provided with an electrical relay and terminal unit, especially a unitfor housing starting and thermal protection relays. In the specification of Italian patent application No. 42916A/81 (GB 2 106 334A)thereisdisclosedastarting relay/terminal box unit, of the positive tempera turecoefficient resistortype, placed on an external wall of the casing shell of a motor-compressor and having such a shape as to have a restricted height relative to the external surface ofthe shell, the connection terminals to a currentfeed line to the unit being arranged to face an operator behind a cooling cabinet containing the compressor. Itwould be desirable for a starting relay/terminal box unit to additionally be able to house a thermal protection relay arranged close to the starting relay in such a way thatthe relays do not thermally influence each otheryetthe unit has compact dimensions and retains the advantages of the known unit. According to the present invention there is provided a hermetically sealed motor-driven compressor pro videdwith an electrical relay and terminal unit comprising a substantially box-shaped housing mounted on the external surface of an uprightwall portion of a casing ofthecompressor,wall means being arranged in the housing to separate a space therein for a starting relayfrom a space therein four a thermal protection relay, and an electrical connection terminal box arranged at an external wall of the housingforelectrical connections to the compressor motor, the unit having a restricted transverse dimension in a direction outwardly from said wall portion of the casing. In a preferred embodiment, the relay and terminal unit comprises a box-shaped outer housing fixed to the external surface ofthe casing shell ofthe motor compressorand insidethe housing there are spaces, adjacent one another, for the starting and thermal protection relays, the spaces being separated by suitable walls. Arranged on a wall ofthe housing is a terminal boxofthecompressor,facing an operator behind a cooling cabinet containing the compressor, the unit having a restricted transverse dimension relative to the external vertical wall of the casing shell. Embodiments ofthe present invention will now be more paticularly described by way of example with reference to the accompanying drawings, in which: Fig. lisa schematic end view of a relay/terminal box unit mounted on the casing shell of a first motor compressor embodying the invention; Fig. 2 is a view of part ofthe relays/terminal box unit; Fig. 3 is a cross-sectional view along the line 3-3 of Fig. 2; Fig. 4 is a schematic circuit diagram of the unit; Fig. 5 is a front view of a relay/terminal box unit on the casing shell of a second motor compressor embodying the invention; and Fig. 6 is a plan view of the unit of Fig. 5. Referring nowto the drawings, there is shown in Fig. 1 a casing shell 10 of a hermetically sealed compressor which is mounted by means of plate 12 connected to the shell and a resilient support 14 on the bottom surface 16 of a compartment 18 atthe back of a lower portion 20 of a cooling cabinet of, for example, refrigerating or cooling apparatus. Fixed laterally to the shell 10its a starting and thermal protection relays/terminal box unit 22, which is closed in the front portion by a cover 24. The unit 22 is connected to a mains network by means of cables 26. With reference to Fig. 4, the electrical feed circuit of the motor compressor is formed by a thermal protection relay 28 provided with a bimetallic blade 30 and, according to the type used, a heating resisance 32 having a function which will be described later. The relay 28 is connected in circuit with two windings of an electric motor 34, more particularly with a working winding 36 and a starting winding 38. Connected in series with the starting winding 38 is a starting relay 40 of the positive temperature coefficient resisitor (PTCR) type. With reference to Fig. 2, the unit 22 comprises an outer housing 43 of plastics material, inside which, in suitable housing spaces separated by walls, are arranged the starting relay 40 and the thermal protection relay 28. Arranged on an outer lateral wall 42 ofthe housing 43 isa terminal box 44 comprising screwterminals 46 and "FASTON" (Trade Mark) spade connectors 48 for electrical connections to the circuit of Fig. 4. As shown in Figs. 1 and 3, the space occupied bythe unit 22, taken along a line perpendicularto the vertical wall of the shell 10 as represented by H in Fig. 1, is very restricted. The dimension of the unit 22 is thus very reduced in thetransverse direction. Afurther advantage is that by arranging the terminal box 44 on an external wall of the housing 43 so thatthe terminals 46,48 face an operator behind the cover 24, it is easierforthe operatorto connect the mains network cables to the terminal box and to carry out servicing. In Figs.5and 6there isshown anotherembodiment, in which another type ofthermal protection relay 50 is employed. The othercomponents shown in Figs. 5 and 6 are otherwise designated bythe same numerals used in Figs. 2 and 3. The relay 50 is of a type commonly used in the motor compressorfield, by contrast with the relay 28 which is produced by Sylvania and sold on the market underthe denomination "glass case protector". It is provided with the heating resistance 32, which has the task of increasing amperometric sensitivity ofthe protector so as to increase the timeforclosing. CLAIMS

1. Ahermeticallysealed motor-driven compressor provided with an electrical relay and terminal unit comprising a substantially box-shaped housing mounted on the external surface of an upright wall portion of a casing ofthe compressor, wall means being arranged in the housing to separate a space therein for a starting relay from a space therein for a thermal protection relay, and an electrical connection terminal box arranged at an external wall of the housing for electrical connections to the compressor motor, the unit having a restricted transverse dimen sion in a direction outwardly from said wall portion of the casing.

2. Amotor-driven compressorsubstantiallyas hereinbefore described with reference to Figs. 1 to 4 of the accompanying drawings.

3. A motor-driven compressor substantially as hereinbefore described with reference to Figs. and 6 of the accompanying drawings.

4. Refrigerating apparatus comprising a cooling cabinet and a motor-driven compressorasclaimed in any one ofthe preceding claims, the compressor being arranged in the cabinet and the electrical relay and terminal unit being so arranged on said wall portion ofthe casing ofthecompressorthatsaid external wall of the housing faces a rearward side of the cabinet.