AU684956B2 - Control system for smoke exhauster - Google Patents
Control system for smoke exhauster Download PDFInfo
- Publication number
- AU684956B2 AU684956B2 AU24993/95A AU2499395A AU684956B2 AU 684956 B2 AU684956 B2 AU 684956B2 AU 24993/95 A AU24993/95 A AU 24993/95A AU 2499395 A AU2499395 A AU 2499395A AU 684956 B2 AU684956 B2 AU 684956B2
- Authority
- AU
- Australia
- Prior art keywords
- motors
- contact
- control system
- electrical power
- central processing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P1/00—Arrangements for starting electric motors or dynamo-electric converters
- H02P1/16—Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters
- H02P1/54—Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters for starting two or more dynamo-electric motors
- H02P1/56—Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters for starting two or more dynamo-electric motors simultaneously
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S454/00—Ventilation
- Y10S454/906—Noise inhibiting means
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Control Of Multiple Motors (AREA)
Description
A I 1 CONTROL SYSTEM FOR SMOKE EXHAUSTER The present invention relates to a smoke exhauster, and more particularly to a control system for the smoke exhauster.
A typical smoke exhauster comprises two motors for driving fan blades in order to exhaust smoke. Normally, the rotational speed of the motor is adjustable for use in different conditions. A typical smoke exhauster comprises a number of resistors arranged in series, a number of contacts arranged between the resistors and a control device movable between the contacts in order to adjust the number of resistors activated to adjust the resistance and thus alter the rotational speed of the fan blades. However, the resistors can generate heat and they may be heated to a temperature up to 270°C. Any gas leaking in the vicinity of the exhauster may be ignited by this high temperature of the resistors leading to a serious fire potential.
The present invention overcomes or at least ameliorates one or more of the afore-described disadvantages of a conventional smoke exhauster.
20 The primary objective of the present invention is to provide a control system for a smoke exhauster in which no resistors are required for adjusting the rotational speed of the motor such that no heat will be generated.
In accordance with one aspect of the invention, there is provided a control s stem for a smoke exhauster, said system comprising: a central processing unit; a power supply circuit for supplying electrical power to said control system; two motors coupled to said central processing unit; and a switching circuit connected to said central processing unit, said switching circuit including a common contact, a first contact and a second contact, said common contact being connected to said first contact for connecting said motors in parallel to provide sufficient electrical power to start said motors, and said common contact being connected to said second contact for o :15 connecting said motors in series to reduce said electrical power to said motors in order to reduce rotational speed of said motors, said central processing unit connecting said common contact to said second contact after said motors are started.
CC
20 FIG. 1 is an electrical diagram of a control system for a smoke exhauster in accordance with the present invention; and FIG. 2 is a detailed electrical diagram showing a portion of the control system of the invention.
Referring to the drawings, and initially to FIG. i, a control 3 system for a smoke exhauster in accordance with the present invention comprises a microprocessor or a central processing unit (abbreviated as CPU hereinafter). A power supply circuit 20 is coupled to an electrical power supply for supplying power to the control system. The power supply circuit 20 includes a converter for converting AC current to DC current. A stabilizing circuit 30 is provided for stabilizing the electrical power supplied to the control system. A number of switches or buttons 40 are provided for controlling the control system. In particular, a button MULT is provided for control and for switching to the lower rotational speed of the motors. A number of indicating lights 50 are provided for indicating the control modes of the smoke exhauster. A number of protective circuits :15 such as triacs, are provided for filtering the signals and for preventing the electric circuit from generating sparks.
A switching circuit 70 is coupled to the CPU and is provided 9 a for changing the rotational speeds of the motors and for reducing the electrical power to the motors.
20 As shown in FIG. 2, Ll and Rl represent two motors of the smoke exhauster. The switching circuit 70 includes a relay switch 71 which includes a common contract COM, a contact NC for coupling the motors L and X,1 in parallel, and another contact NO for coupling the motors Ll and Rl in series. When the relay switch 7; is connected to the contact NC for coupling the motors LI and Rl in parallal, the power supplied
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4 to the motors LI and RI is in normal condition and provides sufficient electrical power to start the motors LI, Rl.
However, when the relay switch 71 is connected to the other contact NO and thus couples the motors Ll and Rl in series, the electrical power to the motors LI and R1 is reduced to one quarter of the original power, thus greatly reducing the rotational speed of the motors LI, Rl and, consequently, simultaneously reducing the noise generated by the motors LI, R1. Accordingly, the switching circuit 70 may be called a "silencing circuit".
In operation, when the button MULT is operated, the CPU connects the relay switch 71 to the contact NC for coupling the motors LI and Rl in parallel. The electrical power supplied to the motors LI and R1 is sufficient so that the motors LI, R1 may be easily started. After the motors are started or after the relay switch 71 is connected to the contact NC for about 3 seconds, the relay switch 71 is connected to the other contact NO for coupling the motors LI and Rl in series, thus reducing the electrical power supplied 20 to the motors Ll and Rl to one quarter of the original power supplied with a consequent reduction in rotational speed of the motors LI, Rl and an associated reduction in the noise generated by the motors LI, Rl.
It is to be understood that the present disclosure has been made by way of example only and that numerous changes in the
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detailed construction and the combination and arrangement of parts may be undertaken without departing from the spirit and scope of the invention as defined in the following claims.
S
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Claims (2)
1. A control system for a smoke exhauster, said system comprising: a central processing unit; a power supply circuit for supplying electrical power to said control system; two motors coupled to said central processing unit; and a switching circuit connected to said central processing unit, said switching circuit including a common contact, a first contact and a second contict, said common contact being connected to said first contact for connecting said motors in parallel to provide sufficient electrical power to start said motors, and said common contact being connected to said second contact for 15 connecting said motors in series to reduce said electrical power to said motors in order to reduce rotational speed of said motors, said central processing -nit connecting said common contact to said second contact after said motors are started. C 20
2. A control system substantially as herein described with reference to the accompanying drawings. DATED THIS eighteenth DAY OF September 1997. CHAO-CHENG CHIANG and CHI-SHYONG CHIANG BY PIZZEYS I MW ABSTRACT A control system for a smoke exhauster includes a CPU, two motors and a switching circuit connected to the CPU. The switching circuit includes a common contact, a parallel contact for connecting the motors in parallel, and a series contact for connecting the motors in series. The common contact is connected to the parallel contact to provide sufficient electrical power to start the motors, and the common contact is connected to the series contact for reducing that electrical power to the motors to reduce the rotational speed of the motors after the motors are started. 0 *4 a C C a a o n
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/431,135 US5623400A (en) | 1995-04-28 | 1995-04-28 | Control system for smoke exhauster |
| GB9514360A GB2303503B (en) | 1995-04-28 | 1995-07-13 | Control system for smoke exhauster |
| AU24993/95A AU684956B2 (en) | 1995-07-13 | 1995-07-13 | Control system for smoke exhauster |
| CA002153957A CA2153957C (en) | 1995-04-28 | 1995-07-14 | Control system for smoke exhauster |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU24993/95A AU684956B2 (en) | 1995-07-13 | 1995-07-13 | Control system for smoke exhauster |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU2499395A AU2499395A (en) | 1997-01-23 |
| AU684956B2 true AU684956B2 (en) | 1998-01-08 |
Family
ID=3713868
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU24993/95A Ceased AU684956B2 (en) | 1995-04-28 | 1995-07-13 | Control system for smoke exhauster |
Country Status (1)
| Country | Link |
|---|---|
| AU (1) | AU684956B2 (en) |
-
1995
- 1995-07-13 AU AU24993/95A patent/AU684956B2/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| AU2499395A (en) | 1997-01-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MK14 | Patent ceased section 143(a) (annual fees not paid) or expired |