Purdue University
Purdue e-Pubs
International Compressor Engineering Conference
School of Mechanical Engineering
1984
An Application of TRIAC to Capacitor Motor for
Hermetic Compressor
K. Nakane
Y. Tozaki
H. Sakamoto
Follow this and additional works at: http://docs.lib.purdue.edu/icec
Nakane, K.; Tozaki, Y.; and Sakamoto, H., "An Application of TRIAC to Capacitor Motor for Hermetic Compressor" (1984).
International Compressor Engineering Conference. Paper 449.
http://docs.lib.purdue.edu/icec/449
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AN APPLICA'l'ION OF 'l'RIAC TO CAPACI'l'OR 1-10'l'OR
FOR lll~Rt~IC'riC COMPRSSO!l
Ka.zuhiro Nakane, Yasuhiro To?.nki,. Ilirota.ka Sakamoto
Shizuoka. Worlw, Mitsubishi Electri.c Corporation
Shizuoka City , Ja.pan
ABSTRACT
This paper refers to a.n n.pplication study of 'l'lUAC
to PSC motor for thft hermetic compessor. It is
1-1ell lcnown that 'l'HIAC rlel nys pharJa ane,le of the
current and has no losses if it is consider(\ as
ideal flwitch. 'l'herefore it is possible to c;et a
ldncl. of variable capacitor lJy connecting ~'HIAC
Nith capacitor in series antl controlline; the firing angle of it.
oncy and output rati.ngo are 100 V,50/60 J!v. and
100 11. It is a. 1mi 1 t-in motor for the rotary type
hermetic compressor shown in Ji'ie;. 2. 'l'hore are
three types of the wirings of the starting device
for thifl motor,as shown i.n lcig, 3. A shows CSR
moto:r,n shows P'l'C asoist CSR motor and C sho~1s
PTC nssist PSC motor. The customer is able to
choono a most suitable type of them for use.
By use of this vari.able capa.ci.tor for PSC motor,\·11:>
could obtain the performance similar to CSR motor.
Therefore ~1e bel iove that this type motor should
be developed as one of the single phase motor for
the hermetic compressor with the progress of the
electronics.
JN'rRODUC'I'ION
Various kinds of single phase induction motors
such as PSC,CSR,CSIR,RSIR,PTC assist PSC and PTC
assist CSR are used for hermetic compressors. 1-1e
choice one of these according to the purpose for
use.
In recent years,it is prosperous to tr,y the application studies of semiconductors to the sphere of
the motor control. An application study of TRIAC
to a single phase induction motor is one of these.
As explainning in this paper,it
a ki.nd of varialJle capacitor 1Jy
in series with capacitor of PSC
line; the firing angle of it. We
motor TRIAC assist PSC motor in
Fig.1 100 W motor used for test
is possible to cet
connecti.ng 'l'RIAC
motor a.nd controlcall this type
this paper.
This paper refers to the torque characteristic of
'l'RIAC aasist PSG motor and the starting· performance on the actual hermetic compressor,bas ed on
the experimental results. And we try to compare it
with the other existing motors. In addition, we
view a possibility of TRIAC assist PSC motor for
hermetic compressors.
TEST MOTOR ANTI CONTROL DEVICE OF 'l'RIAC
2 poles,single phase induction motor shown in Fie;.
l was used for our experiment. its voltage,frequ -
Fig.2 Rotary type hermetic compressor
168
l
1: Main winding
z:
A: CSR motor
3:
4:
5:
6:
7:
Auxiliary
\>tin ding
Relay
Starting
capacitor
Discharging
resistor
Running
capaiitor
P'l'C
thermistor
Fir;. 5 shows the control device of TRIAC made for
our ~xpcriment. Fir;. 6 shows its block diae;rnm,
and Fir;. 7 shows its time charts. It is possible
to set 11p the firinr; o.n(\le of 'l'RIAC lJY 0. l. mace.,
uain~ thjs cotrol device. The detection circujt
for the au:x:Uiar;v Hinrlinr; val tar,e operates to
turn TRIAC into no fire. For this operation, we
make usc of the property which the auxiliary Hi.ndinr; voltsr;e increases with revolution in PSC motor
,as ~hown in Fig. B. And the relation between the
auxil iar;v winding voltnr;e nncl the oper;J.tinr; point
of the detection circuit has a hysterisis characteristic as shown in Fig. B.
B: FTC assist CSR motor
1
C: FTC assist PSG motor
Fig. 3
Wiring diagrams of the hermetic
compressor motors for refrigerator
Fig. 5 Control device of TRIAC
Fir;. L1 sho~rs the Wl-rl-ng diae;ram of TRIAC assiot
PSC motor described in this paper. TRIAC is connected in series with capacitor of PSC motor.
Heoti fioation
ht tenation
Voltage comparator
D
TRIJ\C
\
0J
\
Main
.---winding
Auxiliary
winding
A: To main •1nd1ng
~·o running c•pacitor
C: To auxiliary winoint
\.
Runn1ng
capacitor
Fig. !1
Wiring_diagram of
TRIAC assist PSG motor
B:
D: To common
Fig. 6
169
Block diagram of the control device
Source
voltage
~~~vvv
lr
II
lr
1 1 II
V 1 I
/'\
,,v
1 r 11
I
winding! A
Aux.
voltase
II
1
ditector
Counters
Latches
Zero
lr
ll
,1
,,
,1
V
A
V
1\
(\
\J'C
(\
(\
V~\..J\,
I
• 1 11
I
I
I
I
Firing angle
= o<>
../ v~f· :evel
"'
fica-:.:=:~;;~=:::::::::::::::::=:;:===::=:::::
,-tion
Fig. 9
Recti
- - -... Time
I
I
I
Firing angle
= 180"
Definit ion of the firing angle
Attenation
Vol tase
comparator
Control
Drivers
logic
_uL...-JL..-L-...L.-JII__._....L.-J
[l
[\
An
\1\1\
v v 1V\/
\:
---- --- Time
Fig. 7
H
nl
Time chart of control device
..-I
!il{;h
"0
:.>
.0
i
.
.....
.5
Slip
I
d
bO
~ .. 30
'-'
bO
<11
r-l
S...
<11
..-I
Speed
0
Fig. 8
Main winding
current
60
ii'o
!!
Fire
No fire
Illustr ating the relation ship
between speed-t orque
.
aux. voltage curves and fire
of TRIAC
. 90
Fig. 10
Illustr ating the phase angle
relation ship between main
winding current and aux. winding
current (Base is source voltage )
correspo~ding to slip,fo r PSG motor
TORQUE C!IARACTERRISTIC OF TRIAC ASSIST PSC MOTOR
We define the firing angle of TRIAC as shown in
Fig, 9 in this paper, i.e.,?:er o riee,ree of the
firing angle correspo nds to zero d.egree of the
source voltage. Ji'ir,. 10 shows the phase angle of
the main winding and auxiliar y winding currents
for PSC motor used for our experime nt,which the
source voltage is base. General ly,the main winding
current lags the source voltage, and the auxiliar y
1~inding current leads the source voltage. '
'!'here fore, in case that the firing angle of TRIAC
is zero degree, the auxiliar y l·linding current is
chopped by angular lead for the source voltage.
Fie,-. 11
sho~1s
the measured waveform s of the source
vol~ege (E ) and the auxiliar y winding current
1
(I ) correspo nding to the firing angle of 0" 47-5°
1
a
and 7 3.4 ° s,t slip~l (at starting ) for TRIAC assist
PSC mo·tor. As seen from this figure,t he phase '
angle of I lags as the firing engle of TRIAC
a.
increase s. That is to say,it shows the characte; -·
ristic of a kind of variable inductan ce.
"
170
1000
2000
Spee d (r.p .m.)
Fig. 12
Firi ng angl e
=73. W
Fig. 11
Mea sured spee d-to rque curv e
for TRIAC assi st PSC moto r
The relat ion betw een the start ing torqu
e and the
firinB ' angle of TRIAC is sho\m in Fig.
valu es of the start ing torqu e were obtai13, Thes e
above meas ured spee d-tor que' ourv es. As ned from
seen from
this figu re,th e maximum poin t of the
start ing
torq1.1e is given at the firin g angle of
near ly 50
degr ees. Its value is abou t 3·3 time s
as
much as
the start ing torqu e of PSC moto r,whi ch
broke n line 'in Fig. 13. And in this figui's shown as
sta.r ting torqu e equa ls zero at the firin re,th e
g angle of
near ly 115 degr ees. It means sino< . ..
0
equa tion (1), i.e.t he phase diffe renc in the· · · ·
e betw een the
Mea sured aux. wind ing curr ent
tif TBIAC assi st PSC moto r (slip =l)
00
0
000
Star ting torqu e of PSC moto r is exp~e
ssed as the
follo~ting equa tion, as well
known.
0
°
0
0
00
(1)
0
0
0
0
wher e
I mr . Main wind ing curre nt
Ias Aux iliary windi ne; curre nt
0(1 Phas e diffe renc e betw
een I
T s
6
Sta~ting
torqu e
3000
0
0
m and I a
oo
10
0
·
Ther efore it ie poss ible to cont rol Ts
by cont rolling Iasin ~, i.e., by cont rolli ng the
fi~in
- - - - - - - - - - _qo -
~Starting torq ue of PSC
g
angle of TRIAC for TRIAC assi st PSC moto
r.
Fig. 12 shows the meas ured moto r spee
d-tor que
curv es for TRIAC assis t PSC moto~,corr
eepondine;
to each firin g angle shown in Fig. 11.
meas ured f~om firin g angle of 0 degre They are
degr ees. It is appa rent that the speee to 140
curve chang es as the fir).n g angle of d-tor que
TRIAC chang es
0
0
0
0
b
Fig. 13
171
3b
6b
9b
1
Firi ng angl e (deg ree)
1~0
I
I
Rela tion betw een meas ured
star ting torq ue and firin g ,
angl e for 'rRIAC ·ass ist PSG moto
r
main winding current and auxiliary winding current
becomes zero degree at this firing angle. Increasing more than this firing angle 1 the-auxiliary
l'linding current lags the main tlinding current 1
i.e, sj_nO(<O; T < 0 in'the equation (1). It
torque of PSC motor,whioh is shown as broken line
in Firr. 14.
IPig. 15 sho1-1s the rela.tj on between the starting
~.nd llreak-down torque and the firing angle of
'l'fi.IAC. 'l'he values of the torques are expressed a.s
ratio,~lhich is 1 in case of PSG motor. 'l'he pointe
of the maximum startinr.; and break-down torque
corresponding to the firing angle of 'rRIAC shift a
:fel·l. And the starting torque is high ratio more
-blum -the break-c-lown torque.
B
.
means the motor rotates in reverse.
Fig. 14 shows the relation between the break-down
torque and the firing angle of 'l'RIAC. These values
of' the break-dolm torque Here obtained from above
measured speert-torque curves in the same manner as
the stfl.rting torCJ_ne. As aeon from this figure,tho
maximum point of tho break-down torq\te is Bi von at
the firing angle of nearly 55 degrees. Its value
ierabout 1.4 times as much as the break-down
70
0
U)
p,
4
.jJ
U)
.
Oo
~~3-
0
oo
oooo oo.
oo
00
00
~
H
p:;
0
2
E---1
0
I
. Starting torque
·rl
UlO
oo
•r-t
I:>. A J:>.J:>.I:>.
.jJ
m 1-
A;AI:>.I:>.AAI:>.~:>.AA~~O
H
QJ
;:J
o•
H
0
8
-,r-,0]1----~~~~r-,--,--,,--,--.--TI--r--rj--rl
120
90
60
30
0
-1,
0
Firing angle (degree)
Fig. 14
Relation between measured
break-down torque and firing angle
for TRIAC assist PSC .motor
F'ig. 15
30
60
120
90
Firing angle (degree)
Relation between the starting
a~d break-down torque ratio
(PSC=l) and firing angle
for.TRIAG assist PSG motor
El ~~~~~~~~~~~~
Ea~Wi~~~~hF~+f~~~t,+~~Hw.~ft~~~~~~~~~~~~f~=~-l~~.;~:~.!·~~i~-~~~u~~~~~~~,,~:~
11 -~:..r:'l. .. r\:
A
.l·msec.
E1 ; Source voltage
Ea; Auxiliary winding
voltage
Fig. 16
I 1 i Common line current
Auxiliary winding current
I m'• Main winding current
Iai
Starting test data of TRIAC assist PSC ·motor
on the actual hermetic compressor
172
STAUTTIW PERFORMANCE ON THE AC'I'UAL HERMETIC
COMPRESSOR
Fig. 16 shows the electr ical perfor mance data of
TRIAC assist PSC motor from start to full speed on
the actual herme tic compr ssor shown in Fig. 2. It
shows the case that the firing angle of TRIAC is
setted up at 50 degree s,whi.c h we can ge.t the
maximum value of the starti ng torque . From a
practi cal point of view,w e need set up the firing
angle to take into coside ration of the starti ng,
break- down or transi ent accera ted torque s cooperat ed with the loadin e torque in the system .
TRIAC is turned . into no fire at the point A shown
in Fig. 16. At this point, the detect ion circu it
foi: the auxili ary windin g voltag e of the
contro l
device shown in Fig. 5 operat e,and the motor
change s to the condit ion of PSC.
CDr1PARISON OF TRIAC ASSIST PSC MOTOR WITH TilE
EXISTING OTHER MOTORS
We make the perfor mance compa rison of TRIAC assist
PSC motor with the existi ng other motors using the
experi menta l result s obtain ed by changi ng the ·
electr ic parts except for the runnin g capac itor of
the motor shown in Fig. 1.
70
CSR..
60
o--\-- -1-t'- -i
10
.-7__,--
~
Fig. 18 shows the break- down torque of TRIAC
assiet PSC motor at the firing angle of 55 degree
s
,tcget her with the existi ng other motor s. As seen
from this figure, TRIAC assist PSC motor at the
firing angle of 55 degree s and GSR and PTC assist
CSR m~tors having nearly 20 1-l F starti ng capac itor
have vnear ly eq,ual value of the break- down torque
.
And the breal<-down torque of 'l'RIAG asai.st PSG
motor is nearly 1.8 times value as that of PTC
assist PSG motor having 15n PTC,and nearly 1.5
times value as that of FTC assist PSG motor having
33 n PTG.
H
0
+'
o..-.. o
H
0
+'
s. s ao
0
Olf\U
o:n
p.,
..-l
+' b.O
Ul 1'1
·rl C\l
Ul
Ul b.O
C\li::
·rl
u I-<
~-rl
HI">-<
P<---
+'
Ul
hO
7J<ll
t
PTC:l 5.o
0
60
I
H
80
o--.
Start ing capac itor
+>•
PTC assis t CSR motor
CSR motor
~ Jl'
Olf\
Slf\
(tJF)
p.,
QJ
H
0
~
0
+> +'
0
a 0a
u
u
o:n p..
o:n
p..
rl
+'b.O
-~Ul ffi
•rl
Ul
Ul
(1j
Ultto
C\'51'1
·rl
Ul-<
0
8
p..
t.---A
.
PTC: assist CSR
(PTC=33Q)
~
I
~~
p:;.,_.
8
Fig. 17
PTC=33.o.
o \
50
J1
20
0
o-------~~ ~--
I-t
0
0
o:n o:n
p..
-1 ~
<ll p..
/""
+'
..
.,
c~Ko
~
Ql
;:j
0"
0
I-<
0
(P'rC: l5Q)
flO
0
0
+'
CSR
PTC assis t
alOO
0
PTC assis t CSR
(P'l'C=33n)
,/
PTC=33.Q.
Ereak- down torgue
assia~
/7'
~~,;._
P'rC=1 5&
Fig. 17 shows the starti ng torque of TRIAC assist
PSC motor at the firing angle of 50 degree s,
togeth er with the existi ng other motors . As seen
from this figure, TRIAC assist PSC motor at the
firj.ng angle of 50 degree s, and CSR and PTG assist
CSR motors having nearly 30 1-' F starti ng capao i tor
have a nearly eq_ual value of the starti ng torque .
And the starti ng torque of TRIAC assist PSC motor
is nearly 1. 3 times value as that of PTC assist
PSG motor having 15 n PTG,and nearly 1.4 times
V!l.lttc as that of PTC aesist PSC motor
having 33 g
PTC.
0
(PTC:~ ;~.
PTC
Starti ng torgue
+'
1-
20
I
I
40
60
80
Start ing capac itor ·
(pF)
PTC assis t CSR motor
asrr motor
1/J
·rl
Ul
Ul
<U
t.)
8
p..
8
Measu red start ing torqu e comp arison
of TRIAC assis t PSC motor with the
other motor s
Fig. 18
173
Measu red break -down torqu e
comp arison of TRIAC assis t PSC
motor with the other motor s
VIEW IN FU'rURE OF TRIAC ASSIST PSC MOTOR FOR THE
HERMETIC COMPRESSOR
for restartin~,different from PTC assist PSC or
FTC assist CSR motor.
'l'1>ble 1 shows the coat comparison of the electric
parts for various types of mot~ under nearly same
value oondi·tion of ·the atartine; torque. As seen
from this table,TRIAC assist PSC motor is not the
best one of the minimum cost for performance.
As there is a possibility of cost doHn for the
control device by the mass·production or the
integration 1 it is enough to say that TRIAC assist
FSC motor has a possibility of a practical use i~
future.
CONCLUTION
~
A
B
Starting
capacitor.
16
-.e---
Running
capacitor
27
~
)€
Relay
c
D
·vv
-
....,....._
IVIV L
1/IV~
IV -- L
IV1/IV
55
Discharging
resistor
PTC
2
26
TRIAC ..R
Control
device
Total
<::oat
125
100
69
53
152
Numerical value
CSR
: Ratio
B: PTC assist CSR
(Total cost
C: P'l'C assist PSC
of A=lOO)
D: TRIAC assist PSC
J\:
Table 1
Cost comparison of the electric
parts for various types of motors
(under nealy same condition of
the starting torque)
Ilut the existing motors have some technical problems to be solved. For example,CSR motor has a
meohanical relay to break the circui-t of the
starting capacitor,therefore it has the problem of
a noise with on-off 1 which is a.n unavoidable problem. And although P'rc assist CSR motor achieves
the purpose to do away the mechanical relay,it has
a fault that the motor is not able to be restarted
immediately. Decause PTC is required the time for
cooling to be a initial registanoe after the power
supply was turned off. And FTC assist PSC motor
has a same fault as PTC assist CSR motor 1 in add.ition,ita value of the starting torque is insufficient in comparison with other motors.
TRIAC assist PSC motor has some superior ohracteristics comparing with these existing motors. For
exa.mple 1 the mechanical relay is not necessary,
therefore it has not the problem of a noise. In
addition,it is possible to get the starting torque
It is possible to control the motor torque by
connecting 'I'RIAC in series ~1i th oapaci tor of FSC
motor and controlling the firing angle of it.
We obtained the following experimental results in
100 W motor for the hermetic compressor.
(1) The value of the maximum starting torque of
TRIAC assist FSC motor is about 3-3 till)eS as
much as the starting torque of PSC motor,and
s.bout 1. 3 times as much as the starting torque
of PTC assiot P3C motor having 15u PTC,and
about 1.<1 ti.mes as much as the starting torque
of P'rc aesist FSC motor having 33 n FTC. And·
it is· corresponding to CSR or PTC assist CSR
motor having nearly 30j~F starting capacitor.
(2) The value of the maximum brealt-down torque of
TRIAC assist FSC motor is about 1.4 times as
much as the break-down torque of PSC motor,and
about 1.8 times as much as the break-down
torque of PTC assist PSC motor having 15 Sl FTC
,and about 1.5 times as much s.s the break-down
tortJUe of P'rC assist FSC motor having 33 n PTC
• And it is corresponding to CSR or PTC assist
CSR motor having nearly 20 ~ F starting capacitor.
(3) The maximum point of starting torque is given
at tho firing angle of nearly 50 degrees,and
that of·break-dotm torque is given at 55
der;rees. They shift a little with each other.
TRIAC assist FSC motor has some superior characte~
ristios comparing with the other existing motors.
Although ue cannot to say that it has a sufficient
practical use with the present cost level,it
should be developed as one.of the single phase
motor for the hermetic compressor \~i th the progress of the electronics.
We reported as for the application of TRIAC to
existina PSC motor in this paper. After this it is
necessary for us to investigate to make the motor
design most suitable for THIAC assist PSC motor,
and tre shall continue to study.
REFTIJTIENCES
(1) S. 011aki , "Characteristics of condenser motor
controlled by antiparallel connected thyristors" 1 'J'he .iournal of the Electric Society of
Japan , 1978
(2) Y. Yoshida , M. Tria , S. Ozaki 1 "On the
variable torque characteristics of capacitor
motor drive by 'l'RIAC" , The "journal of the '
Electric Society of Japan , 1983
174