Pumps – Condition responsive control of pump drive motor – By control of electric or magnetic drive motor
Reexamination Certificate
1999-06-16
2001-03-27
Thorpe, Timothy S. (Department: 3746)
Pumps
Condition responsive control of pump drive motor
By control of electric or magnetic drive motor
C417S042000, C318S778000, C318S808000
Reexamination Certificate
active
06206643
ABSTRACT:
CLAIM OF PRIORITY
This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application for METHOD FOR CONTROLLING RECIPROCATING COMPRESSOR HAVING VARIABLE CAPACITY earlier filed in the Korean Industrial Property Office on Jun 17, 1998 and there duly assigned Serial No.22680/1998.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a compressor for a cooling apparatus, and more particularly, to a method for controlling a reciprocating compressor having variable capacity, which is capable of varying a rotational speed thereof.
2. Description of the Related Art
Generally, a compressor is used for compressing a refrigerant at a high temperature and a high pressure, which circulates in an apparatus for generating cool air. There are many kinds of compressors such as a reciprocating compressor, a rotary compressor, a brushless direct current (BLDC) compressor and an inverter type compressor.
A single-phase induction motor is typically used in the reciprocating compressor and the rotary compressor. As shown in
FIG. 1
, a frequency of 50 or 60 Hz is used to start the compressors. In the above mentioned compressors which use the single-phase induction motor, only an on/off operation of the compressors is controlled without any variation of a rotational speed thereof.
Meanwhile, in an reciprocating compressor having variable capacity, the rotational speed of the compressor can be controlled by varying a supplied voltage or frequency. Therefore, a flow rate of the refrigerant is facilely adjusted by the variation of the rotational speed of the compressor, whereby the cooling apparatus itself can be directly controlled.
FIG. 3
shows a structure of a control board in connection with the reciprocating compressor having variable capacity.
In the
FIG. 3
, a motor
1
of the reciprocating compressor having variable capacity is driven by an inverter
3
operated by an output signal from a programmable array logic (PAL)
2
. The PAL
2
is controlled by a microcomputer
10
. The rotational speed of the motor
1
is input to the microcomputer
10
through a back emf sensing part
4
. Therefore, the microcomputer
10
precisely controls the speed of the motor
1
referring to the input data of the speed of the motor
1
.
The microcomputer
10
comprises a mode selecting part
11
, a commutator
12
which receives a signal from the mode selecting part
11
and outputs a commutation signal to the PAL
2
, a step signal generating part
13
which generates a step signal and transmits the step signal to the mode selecting part
11
, a digital-phase shifter
14
which converts the signal of the rotational speed from the back emf sensing part
4
into a correspondent digital phase shifter signal and transmits the digital phase shifter signal to the mode selecting part
11
, and a PWM pulse part
15
which applies a pulse width modulation (PWM) signal to the PAL
2
.
However, in the above mentioned reciprocating compressor having variable capacity, there is a problem that, since an angular velocity of a shaft of the compressor is much lower than that of the conventional compressor using the single-phase induction motor, a lubricating oil is not sufficiently supplied to a sliding portion of the compressor when the compressor is operated at a minimum speed, whereby a reliability of parts of the compressor is lowered.
To overcome the above problem, there has been suggested a method which starts a compressor at a frequency of 58 Hz. However, in the method, there is a problem.
In addition, in the conventional reciprocating compressor having variable capacity, there is a problem that a noise and vibration due to a sudden change of the rotational speed of the compressor is generated when changing the speed from the maximum to the minimum or reversely.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to secure the reliability of the parts of the compressor when starting and reduce the switching loss of the control board.
The other object of the present invention is to minimize the generating of the noise and vibration due to a sudden change of the rotational speed.
To achieve the above objects and other advantages, there is provided A method of controlling a reciprocating compressor comprising of:
starting the reciprocating compressor at a minimum speed in which a frequency of 45-52 Hz is applied; and
operating the reciprocating compressor at a predetermined rotational speed.
Further, according to the present invention, the method according to claim
1
, further comprising a step of operating the reciprocating compressor at a frequency of 52-60 Hz before operating at the predetermined rotational speed.
REFERENCES:
patent: Re. 33620 (1991-06-01), Persem
patent: 2629075 (1953-02-01), Deschmann
patent: 4100466 (1978-07-01), Schroeder
patent: 4401933 (1983-08-01), Davy et al.
patent: 4422030 (1983-12-01), McAllise
patent: 4481455 (1984-11-01), Sugimoto
patent: 4566289 (1986-01-01), Iizuka et al.
patent: 4633382 (1986-12-01), Upadhyay et al.
patent: 4652807 (1987-03-01), Nagura
patent: 4724680 (1988-02-01), Kawai
patent: 4785225 (1988-11-01), Horie et al.
patent: 4959969 (1990-10-01), Okamoto et al.
patent: 5088297 (1992-02-01), Maruyama et al.
patent: 5164651 (1992-11-01), Hu et al.
patent: 5179842 (1993-01-01), Kanazawa
patent: 5422557 (1995-06-01), Lee et al.
patent: 5444344 (1995-08-01), Vincent
Bushnell , Esq. Robert E.
Samsung Electronics Co,. Ltd.
Solak Timothy P.
Thorpe Timothy S.
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