US3200325A

US3200325A - Tap changing voltage regulator for single phase three-wire system

Info

Publication number: US3200325A
Application number: US208836A
Authority: US
Inventors: Takeda Shuzo
Original assignee: Osaka Transformer Co Ltd
Current assignee: Daihen Corp
Priority date: 1962-07-10
Filing date: 1962-07-10
Publication date: 1965-08-10
Anticipated expiration: 1982-08-10

Description

E I Aug. 1955 I SHUZO TAKEDA 3,200,325

TAP CHANGING VOLTAGE REGULATOR FOR SINGLE PHASE THREE-WIRE SYSTEM Filed July 10, 1962 2 Sheets-Sheet 1 R- 3- INVENTQR.

Aug. 10, 1965 SHUZO TAKEDA 3,200,325 TAP CHANGING VOLTAGE REGULATOR FOR SINGLE PHASE THREE-WIRE SYSTEM Filed July 10, 1962 2 Sheets-Sheet 2 55 E1 n a [4% I1 I I /0 RS I I i 26 g- 1 I I 1 3 M30 3 :i/4 i 25 2-c *20 'INVENTOR.

United States Patent O 3,200,325 TAP CHANGING VOLTAGE REGULATGR PG SINGLE PHASE THREE-WIRE SYSTLM Shuzo Takeda, Yodogawa-ku, Osaka, Japan, assignor to )saka Transformer Co., Ltd, @saha, Osaka Prefecture,

apan

Filed July 10, 1962, Ser. No. 208,836 4 Claims. (Cl. 323-435) The present invention relates to an improved tap changing voltage regulator for a single phase three-wire system, and more particularly to an improved tap changing voltage regulator in which the neutral point in a single phase three-wire system is utilized.

One type of prior art tap changing voltage regulator for a single phase three-wire system comprises controlling an auto-transformer, -a series transformer, a reversing switch, and a selector switch and in the above prior art device, output voltage in the secondary coil of said series transformer has been regulated by controlling or adjusting the exciting voltage in the primary coil of said series transformer by means of tap changing in the selector switch or bymeans of polarity-reversing in said reversing switch.

In a device according to the present invention, the above mentioned controlling auto-transformer is not employed in the single phase three-wire system.

The object of the present invention is to provide an improved tap changing voltage regulator for a single phase three wire-system which is capable of controlling voltage over a wider range with a relatively simpler construction and reduced cost for manufacture thereof as compared with prior art devices.

The tap changing voltage regulators of the present invention are markedly different from the prior art devices which employ controlling auto-transformers In a tap changing voltage regulator of the present invention, two input line terminals which are not at the neutral point of the single phase three-wire system are respectively connected to stationary contacts at both ends of a selector switch having five stationary contacts and to the secondary coil of a series transformer. The primary coil of said series transformer is connected to both the center stationary contact of the selector switch and the moving contact of a reversing switch which is for changing input line terminals. And the neutral terminal in the single phase three-wire system is connected to both the stationary cont-acts disposed at the opposed sides of the neutral contact. Since the moving contact of the reversing switch can be shifted in a predetermined order in response to the shifting action of the moving contact of the selector switch, voltage regulation can be effected over a wide range in a relatively simple manner.

In a device according to the present invention, since the controlling auto-transformer which has been absolutely necessary in the prior art devices can be eliminated, the construction of such a voltage regulator device can be simplified and made compact, which results in reduced costs for manufacture of such a device.

In an embodiment of the present invention, the selector switch is provided with two moving contacts and the center tap of a bridge reactor which bridges between these two moving contacts is connected to one end of the primary coil of the series transformer, and the number of regulation steps for output line voltage can be increased by proper arrangement of mutual relations between the moving contact of the reversing switch and the 'ice moving contacts of the selector switch. Furthermore, the primary coil of the series transformer is provided With several taps and these taps are connected through a coarse switch to the moving contact of the reversing switch and by proper arrangement of mutual relations between the moving contacts of the reversing switch, of the selector switch and of the coarse switch, the range of regulation for output line voltage can be increased as in the former case.

In another embodiment of the present invention, the primary coil of a series transformer is provided with a center tap and this center tap is connected through a bridge resistor or bridge reactor and a bridge switch to the neutral terminal of the system, thereby the bridge switch closes just before the moving contact of the selector switch travels to another stationary contact from the previous one and the same opens immediately after said moving contact has moved to said another stationary contact, whereby to prevent failure due to induced voltage from taking place when tap changing operation is being carried out in the selector switch. In this case, since a bridge resistor or bridge reactor is separated from the movable parts of the selector switch and is connected to the center tap of the primary coil of the series transformer, as compared with the prior art arrangement wherein a bridge resistor or bridge reactor is connected to an auxiliary moving contact of the selector switch, the construction of the selector switch by the present invention can be greatly simplified and the same can be formed in a comparatively compact form.

The above and other features and attendant advantages of the present invention will become apparent to those skilled in the art from a reading of the following detailed explanation of several preferred embodiments thereof in conjunction with the accompanying drawings.

In the drawings:

FIG. 1 is an electric circuit diagram of a prior art tap changing voltage regulator for a single phase threewire system;

FIGS. 25 inclusive show the electric circuit diagrams of several preferred embodiments of tap changing voltage regulators according to the present invention respectively.

Now referring to the figures of the drawings, especially to FIG. 1 in which an electric circuit diagram of a prior art tap changing voltage regulator employed for a single phase three-wire system is shown. As seen from this figure,

input line terminals

1 and 2 of the single phase three-wire system are connected to the respective end terminals of a controlling auto transformer AT and

saidinput line terminals

1 and 2 are further connected through the two respective secondary coils 5' and 6 of a series transformer ST to the respective output terminals 10 and 29. The neutral point of the controlling auto-transformer AT is connected to

neutral point terminals

3 and 30. A selector switch SS is provided with

stationary contacts

11, 1 2, 13 and 14- and the three stationary contacts 12, 1'3 and .14- out of these four stationary contacts are respectively connected to each one tap of the controlling autotransformer. The remaining outermost stationary contact 11 is connected to a moving contact 7 of a reversing switch RS whose

stationary contacts

8 and 9 are connected to the respective

input line terminals

1 and 2 and the contact 1 1 is also connected to one end of a primary coil 4 of the series transformer ST. The other end of said primary coil 4 is connected to a moving contact 16 of the selector switch SS. With the above arrangement,

3 by controlling exciting voltage to the primary coil 4 of the series transformer ST through tap changing by the selector switch SS or polarity reversing by means of the reversing switch, output line terminal voltage of the

secondary coils

5 and 6 of the series transformer ST can be The following table indicates that in the above operation, depending upon variance in mutual relations between step positions of the moving contact 7 of the reversing switch RS and step posit-ions of the moving contact 16 of the selector switch SS, output line terminal voltage is ad- 11 5 justable in five different ways.

Table 1 Step position I II 'III IV V Position of moving contact 7 of Contact 9 Contact 9

Contact

8 or 9 or Contact 8.... Contact 8.

reversing switch RS. between them. Position of moving contact 16 Contact 11.; Contact 12 Contact 13 Contact 14.. Contact 15.

of selector switch SS.

According to the present invention, however, the con- In an embodiment as shown in FIG. 3, one end of the trolling auto-transformer AT as shown in FIG. 1 is eli-miprimary coil 4 of a series transformer ST is connected nated, and instead of the auto-transformer necessitated in to the center tap of a bridge reactor 18 connected be the prior art device, as shown in FIG. 2, stationary contween the two moving

contacts

16 and 17. In this

emtacts

8 and 9 of the reversing switch RS are disposed be- 20 bodiment, since the moving

contacts

16 and 17 can also tween the

input line terminals

1 and 2 which are conoperate '11 a bridging position in which these moving nected to the respective

secondary coils

5 and 6 of the contacts are in contact with their respective adjacent sta- Series transformer ST and to the end stationary contacts t-ionary contacts .14- and 1 5 of the selector switch SS in a 1 1 and 15 of the selector switch SS, and the center stabridge-over manner, an intermediate voltage can'be o tionary contact 13 of the selector switch SS is connected tained at the output line terminals, said intermediate to the moving contact 7 of the reversing switch RS tovoltage is a value between the two stationary contacts 14 gether with the primary coil 4 of the series transformer and 15,'and accordingly, the step number for tap chang- ST, and furthermore, the

stationary contacts

12 and 14 ing can be further increased as compared that in an emdisposed adjacent to both sides of said centrally disposed bodiment of FIG. 2. stationary contact 13 are connected to th ut l li The following table indicates that

inthe embodiment terminals

3 and 30. i of FIGJ3; depending upon variance in mutual relations And when the moving contact 1 6 of the selector switch between the step positions of the moving contact 7 of the SS is shifted from the stationary contact 111 to the stasing switch RS a the p positions of the moving tionary contact 15, the moving contact 7 of the reversing Contact 1' 0f the Selector Switdh $5, W line tell switch RS operates as follows in cooperation with the minal voltage is adjustable in nine different y Table 2 Step position I II III IV V VI VII VIII IX Position of moving con- Contact Contact

Contact Contact Contact

9 or 8, Contact Contact Contact Contact tact 7 of reversing 9. 9. 9. 9. or between 8. 8. 8. 1 8. switch RS. 7 them. Position of moving con- Contact Contact Contact Contact Contact 13 Contact Contact Contact Contact tact 16 gig selector 11.- 11. 12. .12. g V, a V .13. 14. 14. 15.

ofrnoving con- Contact Contact, Contact Contact Contact 13. Contact Contact Contact Contact tact 17 of selector 11. y 12. 12. .13. 14. a a 14. 15. 15. switch SS.

selector switch SS, that is, for instance, when the moving FIG. 4 shows another embodiment of the present incontact 1 6 of the selector switch S5 is in contact with the vention, and in this embodiment the primary coil 4 of stationary contact 11 or the stationary contact 12, the the series transformer ST is provided with several taps moving contact 7 of the reversing switch RS comes to and these taps are connectedto the respective stationary contact with the stationary contact9 whilst when the m-

ovcontacts

21, 22 and 23 of the coarse switch CS. In ing contact 1'6 comes to contact with the stationary conthis embodiment, by shifting the moving contact 24 of tact :13, the moving contact 7 of the reversing switch RS thelcoa'rse switch, the step number for top changing can comes to contact with the stationary contact 8 or the stabe increased. ti-onary contact 9, or is in termediately disposed between The following table indicates that in the embodiment the two stationary contacts 8and 9, as shown in FIG. 4, dependingupon mutual relations And when the moving contact 1 6 of the selector switch among step positions of the moving contact 7 of the recomes to contact with the stationary contact 14 or the versing switch RS, step positions of the moving contact stationary contact 15, the moving contact 7 of the revers- 16 of the selector switch SS and step positions of the movm-g switch RS comes to contact with the stationary coning contact 24 of the coarse switch CS, output line tertact 8. rninal voltage is adjustable in nine different ways.

Table 3 1 Step position I II III 1V V VI v11 7 VIII IX Position of moving con- 'Contact Contact Contact Contact Contact9or 8, Contact Contact Contact Contact iiggflofreversmgswitch 9. 9. 9. 9. of} between 8. 8. s 8. 8. Position of moving con- Contact Contact Contact Contact Coni t 13. 7 Contact Contact Contact Contact gzgrt 16 of selector switch 11. 11. 11. 12. 14. 15. 15. 115. Position of moving con- Contact Contact Contact Contact Contact 21. Contact Contact Contact Contact iigt 24 of coarse switch 23. 22. 21. 21. 21. 21. 22. 23.

FIG. 5 shows another embodiment of the present invention and in this embodiment, the primary coil 4 of the series transformer ST is provided with a center tap 25 and this center tap 25 is connected through a bridge resistor or bridge reactor 26 and a bridge switch 27 to a neutral terminal 34 thereby to prevent any failure due to induced voltage taking place in case of tap changing.

In this embodiment, mutual relations between step positions of the moving contact 7 of the reversing switch RS and step positions of the moving contact 16 of the selector switch SS are exactly the same as in the embodiment of FIG. 2 and the output line terminal voltage is adjustable in five different ways. However, in the embodiment of FIG. 5, the bridge switch 27 closes just before the moving contact 16 of the selector switch SS travels to another stationary contact from the previous one, and opens immediately after the moving contact has just arrived at said another contact position. In this way, the bridge switch 27 and the moving contact 16 of the selector switch SS are mechanically related to each other in their operations.

It will be understood that modifications and variations on the embodiments of the invention as disclosed herein may be resorted to Without departing from the scope of the concept of the present invention. Therefore the scope of the invention should be limited only by the scope and proper interpretation of the claims appended hereto.

What I claim is:

1. A tap changing voltage regulator for a single phase three-wire system comprising, in combination, first and second input line terminals and a neutral line terminal, a selector switch having first, second, third, fourth and fifth contacts, a series transformer having first and second secondary coils and a primary coil, each of said secondary coils having an input conductor and an output terminal, first and second input conductors associated with said primary coil, a reversing switch having first, second and third terminals and a movable contact selectively interconnecting said third terminal to said first or said second reversing switch terminal, conductors interconnecting said first input line terminal with said first reversing switch terminal, said first selector switch contact and the input conductor of said first secondary coil, conductors interconnecting said second input line terminal with said second reversing switch terminal, said fifth selector switch contact and the input conductor of said second secondary coil, a third output terminal, conductors interconnecting said neutral line terminal to said second and fourth selector switch contacts and said third output terminal, a conductor interconnecting said reversing switch third terminal with said selector switch third contact, said primary coil first input conductor being connected with said reversing switch third terminal, said selector switch including movable contact means connected to said primary coil second input conductor selectively connecting said primary coil second input conductor with at least one of said first, second, fourth or fifth selector switch contacts.

2. In a tap changing voltage regulator for a single phase three-wire system as in claim 1, a bridge reactor having first and second conductors and a center tap, said primary coil second input conductor being connected to said center tap and said bridge reactor first and second conductors being connected to said selector switch movable contact means and being connectible to two of said selector switch first, second, third and fourth contacts.

3. In a tap changing voltage regulator for a single phase three-wire system as in claim 1, wherein said primary coil includes a plurality of taps and said primary coil first input conductor is selectively connected to one of said taps.

4. In a tap changing voltage regulator for a single phase three-wire system as in claim 1, wherein said primary coil includes a center tap, a bridge resistor having an input connected to said primary coil center tap and an output conductor, a bridge switch having a first terminal connected to said bridge resistor output conductor and a second terminal connected to said third output terminal and means interconnecting said bridge switch and said selector switch movable contact means whereby said bridge switch closes immediately prior to movement of said selector switch movable contact means and opens immediately after movement of said selector switch movable contact means ceases.

Reterences Cited by the Examiner UNITED STATES PATENTS- 2,036,305 4/36 Snyder 323-47 X 2,063,693 12/36 McCarty 323-45 2,770,767 11/56 Nelson 323-45 X LLOYD MCCOLLUM, Primary Examiner. ROBERT L. SIMS, Examiner.

Claims

1. A TAP CHANGING VOLTAGE REGULATOR FOR A SINGLE PHASE THREE-WIRE SYSTEM COMPRISING, IN COMBINATION, FIRST AND SECOND INPUT LINE TERMINALS ANDA NEUTRAL LINE TERMINAL, A SELECTOR SWITCH HAVING FIRST, SECOND, THIRD, FOURTH AND FIFTH CONTACTS, A SERIES TRANSFORMER HAVING FIRST AND SECOND SECONDARY COILS AND A PRIMARY CLIL, EACH OF SAID SECONDARY COILS HAVING AN INPUT CONDUCTOR AND AN OUTPUT TERMINAL, FIRST AND SECOND INPUT CONDUCTORS ASSOCIATED WITH SAID PRIMARY COIL, A REVERSING SWITCH HAVING FIRST, SECOND AND THIRD THERMINALS AND A MOVABLE CONTACT SELECTIVELY INTERCONNECTING SAID THIRD TERMINAL TO SAID FIRST OR SAID SECOND REVERSING SWITCH TERMINAL, CONDUCTORS INTERCONNECTING SAID FIRST INPUT LINE TERMINAL WITH SAID FIRST REVERSING SWITCH TERMINAL, SAID FIRST SELECTOR SWITCH CONTACT AND THE INPUT CONDCUTOR OF SAID FIRST SECONDARY COIL, CONDUCTORS INTERCONNECTING SAID SECOND INPUT LINE TERMINAL WITH SAID SECOND REVERSING SWITCH TERMINAL, SAID FIFTH SELECTOR SWITCH CONTACT AND THE INPUT CONDUCTOR OF SAID SECONDARY SECONDARY COIL, A THIRD OUTPUT TERMINAL, CONDUCTORS INTERCONNECTING SAID NEUTRAL LINE TERMINAL TO SAID SECOND AND FOURTH SELECTOR SWITCH CONTACTS AND SAID THIRD OUTPUT TERMINAL, A CONDUCTOR INTERCONNECTING SAID REVERSING SWITCH THIRD TERMINAL WITH SAID SELECTOR SWITCH THIRD CONTACT, SAID PRIMARY COIL FIRST INPUT CONDUCTOR BEING CONNECTED WITH SAID REVERSING SWITCH THIRD TERMINAL, SAID SELECTOR SWITCH INCLUDING MOVABLE CONTACT MEANS CONNECTED TO SAID PRIMARY COIL SECOND INPUT CONDCUTOR SELECTIVELY CONNECTING SAID PRIMARY COIL SECOND INPUT CONDUCTOR WITH AT LEAST ONE OF SAID FIRST, SECOND, FOURTH OR FIFTH SELECTOR SWITCH CONTACTS.