JPH0368639B2 - - Google Patents
Info
- Publication number
- JPH0368639B2 JPH0368639B2 JP60007705A JP770585A JPH0368639B2 JP H0368639 B2 JPH0368639 B2 JP H0368639B2 JP 60007705 A JP60007705 A JP 60007705A JP 770585 A JP770585 A JP 770585A JP H0368639 B2 JPH0368639 B2 JP H0368639B2
- Authority
- JP
- Japan
- Prior art keywords
- power supply
- switching
- power source
- power
- electric motor
- 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.)
- Expired - Lifetime
Links
- 238000013021 overheating Methods 0.000 claims description 5
- 239000012530 fluid Substances 0.000 description 9
- 238000010586 diagram Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000005856 abnormality Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
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
- H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
- H02P25/16—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring
- H02P25/18—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring with arrangements for switching the windings, e.g. with mechanical switches or relays
- H02P25/20—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring with arrangements for switching the windings, e.g. with mechanical switches or relays for pole-changing
Description
【発明の詳細な説明】
〔発明の技術分野〕
この発明は、可変周波数電源（以下Ｖ電源と略
称する）又は商用電源（以下Ｃ電源と略称する）
のいずれかを択一的に選択して電動機等の負荷に
給電する電源切替装置に関するものであり、特に
電源切替時に発生する電動機の過熱を防止して安
全に運転する技術に関するものである。[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a variable frequency power supply (hereinafter abbreviated as V power supply) or a commercial power supply (hereinafter abbreviated as C power supply).
The present invention relates to a power supply switching device that selectively selects one of the following to supply power to a load such as an electric motor, and particularly relates to a technique for safely operating the motor by preventing overheating of the electric motor that occurs when switching the power source.
第１図は可変周波数(V)電源システムを説明する
図であり、図において、１は商用(C)電源、２はＶ
電源、３，４，５は開閉器、６は電動機、７は回
転体（フアン）、８は流体路、８ａ，８ｂは流体
路８のそれぞれ入口、出口、９は流体路８を通過
する流体量の制御をする機械的制御機構（入口ベ
ーン）１０は流体制御装置、１１は流体制御装置
１０への制御入力、１０ａ及び１０ｂはＶ電源２
及び機械的制御機構９にそれぞれ制御信号を送る
信号線、１２は電力検出器である。
Figure 1 is a diagram explaining a variable frequency (V) power supply system. In the figure, 1 is a commercial (C) power supply, 2 is a V
A power source, 3, 4, and 5 are switches, 6 is an electric motor, 7 is a rotating body (fan), 8 is a fluid path, 8a and 8b are the inlet and outlet of the fluid path 8, respectively, and 9 is the fluid that passes through the fluid path 8. A mechanical control mechanism (inlet vane) 10 for controlling the amount is a fluid control device, 11 is a control input to the fluid control device 10, and 10a and 10b are V power supplies 2.
and a signal line for sending control signals to the mechanical control mechanism 9, respectively, and 12 is a power detector.
第２図は従来の制御回路図であり、図におい
て、BP，BNは制御電源の＋，−母線、１２ａ，
１２ｂは電力検出器１２が所定値以上の電力を検
出したとき、それぞれ閉、開となる接点、１３
ａ，１３ｂは電力検出器１２以外の電源切替条件
を与える条件リレー（図示せず）のそれぞれ動作
時、閉、開となる接点、３Ｔ，５Ｔはそれぞれ開
閉器３，５のトリツプコイル、３Ｃ，５Ｃはそれ
ぞれ開閉器３，５の投入コイル、５ａ，５ｂは開
閉器５が閉のとき、それぞれ閉、開となる接点、
３ａ，３ｂは開閉器３が閉のとき、それぞれ閉、
開となる接点、T1，T2はタイマー、T1a，T2aは
それぞれタイマーT1，T2の接点である。 FIG. 2 is a conventional control circuit diagram. In the figure, BP and BN are the + and - bus bars of the control power supply, 12a,
12b is a contact that closes and opens, respectively, when the power detector 12 detects power equal to or higher than a predetermined value;
a and 13b are contacts that close and open when a condition relay (not shown) that provides power supply switching conditions other than the power detector 12 is activated, 3T and 5T are trip coils of switches 3 and 5, respectively, 3C and 5C are closing coils of switches 3 and 5, respectively; 5a and 5b are contacts that close and open, respectively, when switch 5 is closed;
3a and 3b are closed when switch 3 is closed, respectively.
The contacts that open, T 1 and T 2 are the timer contacts, and T 1 a and T 2 a are the contacts of the timers T 1 and T 2 , respectively.
なお、開閉器５を開、開閉器３を閉とする手段
を第１の開閉手段、開閉器３を開、開閉器５を閉
とする手段を第２の開閉手段と呼ぶこととする。 Note that the means for opening the switch 5 and closing the switch 3 will be called a first switching means, and the means for opening the switch 3 and closing the switch 5 will be called a second switching means.
次に動作について説明する。説明をわかりやす
くするために、第１図を発電プラントのボイラ用
フアンの例として説明する。この時、回転体７は
フアンであり、機械的制御機構９は入口ベーン、
流体路８は風路である。 Next, the operation will be explained. To make the explanation easier to understand, FIG. 1 will be explained as an example of a boiler fan for a power generation plant. At this time, the rotating body 7 is a fan, and the mechanical control mechanism 9 is an inlet vane,
The fluid path 8 is an air path.
Ｖ電源２の運転時は開閉器４，５閉、開閉３開
となっており、電動機６はＶ電源２で駆動され
る。Ｖ電源２の出力は周波数(F)が可変となってお
り、従って電動機６の回転数Ｎは
N9120／Ｐ×Ｆ ……（式１）
Ｐ：電動機６の極数
となり、周波数(F)によって電動機６は可変速運転
される。 When the V power source 2 is in operation, the switches 4 and 5 are closed and the switch 3 is open, and the electric motor 6 is driven by the V power source 2. The frequency (F) of the output of the V power supply 2 is variable, so the rotation speed N of the motor 6 is N9120/P×F (Formula 1) P: the number of poles of the motor 6, which varies depending on the frequency (F). The electric motor 6 is operated at variable speed.
電動機６の電圧EM（即ちＶ電源２の出力電圧）
は電動機６の鉄心飽和を避けるために
EM／Ｆ＝Ｋ ……（式２）
Ｋ：定数
のようにEM／Ｆ＝一定等で運転されるのが一般
的である。 Voltage E M of electric motor 6 (i.e. output voltage of V power supply 2)
In order to avoid saturation of the iron core of the electric motor 6, the motor is generally operated with E M /F=constant, such as E M /F=K (Equation 2) where K is a constant.
フアン７は電動機６により駆動されており、従
って風路８に流れる風量は電動機６の回転数Ｎ、
即ちＶ電源２の出力周波数(F)によって制御される
こととなる。この時、入口ベーン９は風量制御に
関与せず、省エネルギのために風路８の風路抵抗
を小さくしておく必要があり、全開又は全開付近
の一定開度としておく。即ち、信号線１０ａの信
号によってＶ電源２の出力周波数Ｆが制御され、
信号線１０ｂの信号によって入口ベーン９は一定
開度となっている。 The fan 7 is driven by the electric motor 6, so the amount of air flowing into the air passage 8 is determined by the rotation speed N of the electric motor 6,
That is, it is controlled by the output frequency (F) of the V power supply 2. At this time, the inlet vane 9 is not involved in air volume control, and the air passage resistance of the air passage 8 must be kept small for energy saving, and the opening degree is set to be fully open or at a constant opening degree close to fully open. That is, the output frequency F of the V power supply 2 is controlled by the signal on the signal line 10a,
The inlet vane 9 is kept at a constant opening degree by the signal from the signal line 10b.
他方、Ｃ電源１の運転時は開閉器３閉、開閉器
４，５開となっており、電動機６はＣ電源１、即
ち一定の商用電源周波数FCで駆動され、従つて、
フアン７は定速で回転する。この場合には、風路
８の流体量は入口ベーン９によって制御される。
即ち、信号線１０ｂの信号によってフアン７の出
力風量は制御される。 On the other hand, when the C power source 1 is in operation, the switch 3 is closed and the switches 4 and 5 are open, and the motor 6 is driven by the C power source 1, that is, at a constant commercial power frequency F C , and therefore,
The fan 7 rotates at a constant speed. In this case, the amount of fluid in the air passage 8 is controlled by the inlet vane 9.
That is, the output air volume of the fan 7 is controlled by the signal on the signal line 10b.
Ｖ電源２からＣ電源１への切替は開閉器４，５
開、及び開閉器３閉の操作によって行われる。 Switching from V power supply 2 to C power supply 1 is done using switches 4 and 5.
This is done by opening and closing the switch 3.
ここで、Ｖ電源２は大容量電動機に適用するよ
うな場合には、値段をさげるために電動機容量ま
でのＶ電源とせず、通常の運転をＶ電源で行う程
度に小さくすることが多い。このフアンの例のよ
うな時、Ｖ電源２の容量は運転周波数上限を商用
周波数FCのＸ％とすれば、ほゞ（Ｘ／100）3に比例し
た値とすることが出来る。例えば、1000Kwのモ
ータで、力率cosθ＝85％、モータ効率η＝90％の
ときには、電動機容量の1000KwまてＶ電源運転
しようとすれば
1000／0.85×0.9≒1310kVA
程度のＶ電源が必要であるが、通常運転が商用周
波数FCのｘ＝80％の範囲であるとすれば
1310×（80／100）3≒670kVA
のＶ電源に選ぶことが出来る。 Here, when the V power supply 2 is applied to a large-capacity motor, in order to reduce the price, the V power supply is not used up to the capacity of the motor, but is often made small enough to perform normal operation with the V power supply. In the case of this fan example, the capacity of the V power supply 2 can be set to a value approximately proportional to (X/100) 3 if the upper limit of the operating frequency is set to X% of the commercial frequency FC . For example, with a 1000Kw motor, when the power factor cosθ = 85% and the motor efficiency η = 90%, if you want to operate the motor with a V power supply of 1000Kw, you will need a V power supply of about 1000/0.85×0.9≒1310kVA. However, if normal operation is in the range of x = 80% of the commercial frequency F C , a V power supply of 1310 x (80/100) 3 ≒ 670 kVA can be selected.
従って、Ｖ電源２から商用電源１への切替及び
その逆の切替はＶ電源システムでは、運転中にあ
りうることであり、従来は前述の切替操作を電力
検出器１２を用いて行っていた。この場合の切替
について第２図の制御回路で説明する。 Therefore, switching from the V power supply 2 to the commercial power supply 1 and vice versa can occur during operation in the V power supply system, and conventionally, the above-mentioned switching operation was performed using the power detector 12. Switching in this case will be explained using the control circuit shown in FIG. 2.
まず、Ｖ電源２の運転中について説明する。電
力検出器１２にはＶ電源２に印加する商用電源１
の電圧と電動機６への電流が印加され、電動機６
への供給電力を算出し、一定値以上を検出したと
き出力を出すように構成されている。上記電力一
定値をＶ電源２の容量又はその近傍の値に選定
し、電力検出器１２が動作したときに接点１２ａ
を閉とし、従ってトリツプコイル５Ｔをドライブ
して開閉器５を開とし、タイマT1の時限後に投
入コイル３Ｃをドライブして開閉器３を閉として
Ｖ電源２からＣ電源１に切替える。タイマT1の
時限は開閉器３を投入する時、電動機６の残留電
圧が減少するのを待つ時限である。投入コイル、
トリツプコイルの電流はそれぞれ投入、トリツプ
が完了すれば自己しや断するように接点３ｂ，５
ａを用いている。接点１３ａが閉となっても上記
接点１２ａの閉と同様に動作するが、接点１３ａ
はＶ電源２故障の異常時等にＣ電源１に切替える
ために設けてある。 First, the operation of the V power supply 2 will be explained. The power detector 12 has a commercial power supply 1 applied to the V power supply 2.
voltage and current to the motor 6 are applied, and the motor 6
It is configured to calculate the power supplied to the device and output an output when it detects a certain value or more. The above constant power value is selected as the capacity of the V power supply 2 or a value close to it, and when the power detector 12 operates, the contact 12a
is closed, the trip coil 5T is driven to open the switch 5, and after the timer T1 expires, the closing coil 3C is driven to close the switch 3 and the V power supply 2 is switched to the C power supply 1. The time limit of the timer T1 is a time limit for waiting for the residual voltage of the motor 6 to decrease when the switch 3 is closed. input coil,
Contacts 3b and 5 are connected so that the current of the trip coil is turned on, and when the trip is completed, the current is turned off automatically.
a is used. Even when the contact 13a is closed, it operates in the same way as when the contact 12a is closed, but the contact 13a
is provided to switch to the C power supply 1 in the event of an abnormality such as a failure of the V power supply 2.
以上のように接点１２ａ又は１３ａの閉で、第
１の開閉手段によりＶ→Ｃ電源へ切替えられる。 As described above, when the contact 12a or 13a is closed, the power source is switched from V to C by the first opening/closing means.
次にＣ電源１運転中にＶ電源２へ切替える時に
ついて説明する。Ｖ電源２を導通する目的は、省
エネルギを得るためであり、Ｖ電源２の運転領域
ではＶ電源２で電動機６を運転したい。Ｃ電源１
の運転中に電力検出器１２所定値以下（接点１２
ａの開と必ずしも一致しなくてもよい）を検出し
たとき、接点１２ｂが閉となり、Ｖ電源２故障で
はないことを条件（接点１３ｂ閉）、トリツプコ
イル３Ｔをドライブして開閉器３を開とし、タイ
マT2の時限後に投入コイル５Ｃをドライブして
開閉器５を閉としてＣ電源１からＶ電源２に切替
える。タイマT2の時限は電動機６が減速してＶ
電源２による回転とほゞ同じになるまで時間に選
定している。コイル３Ｔ，５Ｃの電流は接点３
ａ，５ｂで自己しや断される。以上のように接点
１２ｂ閉て、第２の切替手段によりＣ→Ｖ電源へ
切替えられる。 Next, a description will be given of when switching to the V power supply 2 while the C power supply 1 is in operation. The purpose of conducting the V power supply 2 is to save energy, and in the operating range of the V power supply 2, it is desired to operate the motor 6 with the V power supply 2. C power supply 1
During operation, the power detector 12 falls below a predetermined value (contact 12
(does not necessarily coincide with the opening of a), the contact 12b closes, and the trip coil 3T is driven to open the switch 3, provided that there is no failure of the V power supply 2 (contact 13b is closed). , after the timer T2 expires, the closing coil 5C is driven to close the switch 5 and the C power supply 1 is switched to the V power supply 2. The time limit of timer T2 is V as the motor 6 decelerates.
The time is set so that the rotation is approximately the same as the rotation by power supply 2. The current of coils 3T and 5C is at contact 3
It is self-cut at a and 5b. As described above, the contact 12b is closed and the second switching means switches from C to V power source.
第３図はＶ電源２からＣ電源１にい切替える時
に発生するトルクを説明する図であり、横軸は切
替前のＶ電源２の運転回転数、縦軸は切替時の発
生トルクを示す。 FIG. 3 is a diagram illustrating the torque generated when switching from the V power supply 2 to the C power supply 1. The horizontal axis shows the operating rotational speed of the V power supply 2 before switching, and the vertical axis shows the torque generated at the time of switching.
第３図によれば、Ｃ電源１への切替前にＶ電源
２で運転されている回転数によって、Ｃ電源１へ
切替える時に発生するトルクが大きい場合（例え
ば70〜80％or20〜40％回転数）があり、これは起
動時のトルクの２〜３倍に達することもある。切
替時の発生トルクが大きいことは、切替時に流れ
る電流が大きいことを示し、切替時に電動機６に
熱が蓄積されることを意味する。 According to Fig. 3, if the torque generated when switching to C power source 1 is large depending on the rotation speed operated by V power source 2 before switching to C power source 1 (for example, 70 to 80% or 20 to 40% rotation This torque can reach two to three times the starting torque. A large generated torque during switching indicates that a large current flows during switching, and means that heat is accumulated in the electric motor 6 during switching.
従来の電源装置は以上のように構成されている
ので、Ｖ電源２からＣ電源１への切替が短時間の
うちに多数回実行されると、切替時の大電流によ
って電動機の過熱が促進され、電動機を焼損に至
らしめることになり、また焼損に至らなくても、
電動機のコイル絶縁劣化を促進して電動機の寿命
を短くする等の欠点があった。 Conventional power supplies are configured as described above, so if switching from V power supply 2 to C power supply 1 is performed many times in a short period of time, overheating of the motor will be promoted due to the large current at the time of switching. , it will cause the motor to burn out, and even if it does not burn out,
This has the disadvantage of accelerating deterioration of the motor's coil insulation and shortening the life of the motor.
この発明は、上記のような従来のものの欠点を
除去するためになされたもので、可変周波数電源
から商用電源に切替えた時に、所定の時間だけ可
変周波数電源にもどす切替をロツクすることによ
り、短時間のうちに多数回、商用電源への切替を
行わせないようにして電動機の異常過熱を防止で
きる電源切替装置を提供することを目的としてい
る。
This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and when switching from variable frequency power source to commercial power source, it locks the switching back to variable frequency power source for a predetermined period of time. It is an object of the present invention to provide a power supply switching device capable of preventing abnormal overheating of a motor by preventing switching to a commercial power supply many times in a given time.
以下、この発明の一実施例について説明する。
第４図において、T3はタイマーである。他の符
号は第２図と同一又は相当部分を示す。
An embodiment of the present invention will be described below.
In FIG. 4, T3 is a timer. Other symbols indicate the same or corresponding parts as in FIG. 2.
第４図において、接点１２ａ又は接点１３ａが
閉となれば、第２図と同様にトリツプコイル５
Ｔ、投入コイル３Ｃにより開閉器５，３がそれぞ
れ開、閉となってＶ電源２からＣ電源１に切替え
られる。その後、直ちに負荷減となって電力検出
器１２の接点１２ｂが閉となったとき、開閉器３
の閉によって接点３ｂが開となっているので、ト
リツプコイル３Ｔ、投入コイル５Ｃはドライブさ
れず、Ｃ電源１による電動機６の運転が継続され
る。開閉器３の閉によって接点３ａが閉となり、
時限T3後に上記３ｂによる投入コイル５Ｃ、ト
リツプコイル３Ｔのドライブ阻止は解除されて、
Ｖ電源２への切替がトリツプコイル３Ｔ、投入コ
イル５Ｃによって行われる。時限T3はＶ電源２
からＣ電源１へ切替えた時に発生する電動機６の
過熱が十分冷却されるだけの時限に選定されてい
る。 In FIG. 4, if the contact 12a or 13a is closed, the trip coil 5
The switches 5 and 3 are opened and closed by the T and closing coils 3C, respectively, and the V power supply 2 is switched to the C power supply 1. Thereafter, when the load immediately decreases and the contact 12b of the power detector 12 closes, the switch 3
Since the contact 3b is opened by closing, the trip coil 3T and the closing coil 5C are not driven, and the motor 6 continues to be operated by the C power supply 1. When the switch 3 is closed, the contact 3a is closed,
After the time limit T3 , the drive prevention of the closing coil 5C and tripping coil 3T by the above 3b is released,
Switching to the V power supply 2 is performed by a trip coil 3T and a closing coil 5C. Time limit T 3 is V power supply 2
The time limit is selected to be enough to sufficiently cool down the overheating of the electric motor 6 that occurs when switching from the C power source 1 to the C power source 1.
なお、以上の説明では電力検出器１２と条件リ
レー１３による切替を同一の時限T3で示したが、
これを分離した時限で示した一実施例が第５図で
ある。第５図において、Ｄ１，Ｄ２はダイオー
ド、１２aTは電力検出器１２ａで駆動される補
助タイマー、１２Ｘ，１３Ｘは補助リレー、
T31，T32はタイマーである。条件リレーの接点
１３ａ閉で補助リレー１３Ｘが動作し、タイマー
T32の間、開閉器３，５の開、閉を阻止し、電力
検出器の補助タイマー１２aT閉で補助リレー１
２Ｘが動作し、タイマーT31の間、開閉器３，５
の開、閉を阻止する。この場合には、電力検出器
１２が動作して、補助タイマー１２aTが動作す
るまでにＶ電源２の出力周波数を上昇させてＶ電
源２の出力上限（例えば80％回転数）まで上げて
おく等が行われる。これは、周波数のジヤンプ
（Ｖ電源→Ｃ電源）巾を小さくして、流体変動量
を小さくするために行われる手段である。 In addition, in the above explanation, the switching by the power detector 12 and the condition relay 13 was shown in the same time period T3 ,
An example in which this is shown in separate time periods is shown in FIG. In FIG. 5, D1 and D2 are diodes, 12aT is an auxiliary timer driven by the power detector 12a, 12X and 13X are auxiliary relays,
T 31 and T 32 are timers. When the contact 13a of the condition relay is closed, the auxiliary relay 13X operates and the timer starts.
During T 32 , switches 3 and 5 are prevented from opening and closing, and auxiliary relay 1 is closed when auxiliary timer 12aT of the power detector is closed.
2X operates and during timer T 31 , switches 3 and 5
Prevent opening and closing. In this case, the output frequency of the V power supply 2 should be increased to the output upper limit (for example, 80% rotation speed) of the V power supply 2 before the power detector 12 operates and the auxiliary timer 12aT operates. will be held. This is a means for reducing the frequency jump (from V power source to C power source) and reducing the amount of fluid fluctuation.
また、上記実施例では、タイマーT3，T31，
T32を一定値として示したが、電動機とその負荷
がきまれば、第３図の特性はきまるので、切替前
の電動機運転状態（回転数）によって、これらの
タイマーを可変しても上記実施例と同様の効果を
奏する。 Further, in the above embodiment, the timers T 3 , T 31 ,
Although T 32 is shown as a constant value, once the motor and its load are determined, the characteristics shown in FIG. It has the same effect as.
以上のように、この発明によれば、可変周波数
電源から商用電源に切替えたときに電動機に蓄積
される熱量を十分定常状態にもどすまで次の切替
を阻止するように構成したので、電動機の熱的破
損を防止でき、また熱的な絶縁劣化を防止して長
期間、安全な運転を続けることができる効果があ
る。
As described above, according to the present invention, when switching from a variable frequency power source to a commercial power source, the next switching is prevented until the amount of heat accumulated in the electric motor is sufficiently returned to a steady state. This has the effect of preventing physical damage and thermal insulation deterioration, allowing safe operation to continue for a long period of time.
第１図はＶ電源システム図、第２図は従来の制
限回路、第３図はＶ→Ｃ電源切替時に発生するト
ルク説明図、第４図はこの発明の一実施例を示す
回路図、第５図はこの発明の他の実施例を示す回
路図である。
１……商用(C)電源、２……可変周波数（Ｖ）電
源、３，４，５……開閉器、１２……電力検出
器、３Ｃ，５Ｃ……開閉器３，５の投入コイル、
３Ｔ，５Ｔ……開閉器３，５のトリツプコイル、
１２ａ，１２ｂ……電力検出器１２の動作時閉、
開接点、T1，T2，T3，T31，T32……タイマー、
１３ａ……条件リレー、なお、図中、同一符号は
同一又は相当部分を示す。
Fig. 1 is a V power supply system diagram, Fig. 2 is a conventional limiting circuit, Fig. 3 is an explanatory diagram of the torque generated when switching from V to C power supply, and Fig. 4 is a circuit diagram showing an embodiment of the present invention. FIG. 5 is a circuit diagram showing another embodiment of the invention. 1... Commercial (C) power supply, 2... Variable frequency (V) power supply, 3, 4, 5... Switch, 12... Power detector, 3C, 5C... Closing coil of switches 3 and 5,
3T, 5T...trip coils of switches 3 and 5,
12a, 12b...closed when the power detector 12 is in operation;
Open contact, T 1 , T 2 , T 3 , T 31 , T 32 ... Timer,
13a...Condition relay. In the drawings, the same reference numerals indicate the same or corresponding parts.
Claims (1)
源及び可変周波数電源と、前記可変周波数電源か
ら前記商用電源へ切替える第１の開閉手段と、前
記商用電源から前記可変周波数電源へ切替える第
２の開閉手段とを有する電源切替装置において、
前記第１の開閉手段により前記電動機の電源を商
用電源に切替え時に作動し、前記第２の開閉手段
の回路に設けたタイマ接点を前記電動機の過熱が
十分冷却される時限だけ開成するタイマを備えた
ことを特徴とする電源切替装置。 ２ タイマの時限を、第１の開閉手段によって商
用電源へ切替える時点の電動機運転状態によって
可変とするようにしたことを特徴とする特許請求
の範囲第１項記載の電源切替装置。[Scope of Claims] 1. A commercial power source and a variable frequency power source that are alternatively selected to supply power to the electric motor, a first switching means that switches from the variable frequency power source to the commercial power source, and a first switching means that switches from the commercial power source to the variable frequency power source. A power supply switching device having a second opening/closing means for switching to a power supply,
a timer that is activated when the first opening/closing means switches the power source of the electric motor to a commercial power supply and opens a timer contact provided in the circuit of the second opening/closing means only for a time period when the overheating of the electric motor is sufficiently cooled down; A power supply switching device characterized by: 2. The power switching device according to claim 1, wherein the time limit of the timer is made variable depending on the operating state of the electric motor at the time when switching to commercial power by the first opening/closing means.
Priority Applications (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60007705A JPS61167393A (en) | 1985-01-18 | 1985-01-18 | Power source switching system |
| KR1019850005224A KR900000767B1 (en) | 1985-01-18 | 1985-07-22 | Overheat preventing system of a.c. motor |
| EP85305375A EP0171245B1 (en) | 1984-07-28 | 1985-07-29 | Overheat preventing system of a.c. motor |
| DE8585305375T DE3583262D1 (en) | 1984-07-28 | 1985-07-29 | OVERHEATING PROTECTION FOR AC MOTORS. |
| EP90116144A EP0409286B1 (en) | 1984-07-28 | 1985-07-29 | Overheat preventing system of A.C. motor |
| DE3588032T DE3588032T2 (en) | 1984-07-28 | 1985-07-29 | Overheating protection for AC motor. |
| US07/494,840 US4977363A (en) | 1984-07-28 | 1990-03-16 | Overheat preventing system of A.C. motor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60007705A JPS61167393A (en) | 1985-01-18 | 1985-01-18 | Power source switching system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61167393A JPS61167393A (en) | 1986-07-29 |
| JPH0368639B2 true JPH0368639B2 (en) | 1991-10-29 |
Family
ID=11673155
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60007705A Granted JPS61167393A (en) | 1984-07-28 | 1985-01-18 | Power source switching system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61167393A (en) |
-
1985
- 1985-01-18 JP JP60007705A patent/JPS61167393A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61167393A (en) | 1986-07-29 |
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| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |