JPH07298480A - Power supply unit for sputter ion vacuum pump - Google Patents

Abstract

PURPOSE:To protect a leakage transformer for feeding power to a sputter 1 on pump. CONSTITUTION:Power is fed to a sputter ion pump 1 from a secondary winding of a leakage transformer 4 through a rectifier circuit 3, and the primary winding of the transformer is connected to an AC power supply unit 6 through a circuit breaker 10. When the breaker is closed, the pump is started and a current is applied to a timer 12. Before a delay operation of the timer, a vacuum pressure drops and if a voltage applied to the pump rises above the normal operating voltage of a meter relay 11 because of a drop in a pump-current I, a normally closed contact 11b opens and the energization of the timer is canceled. If a voltage applied to the pump does not reach the operating voltage of a meter relay within a delay time of the timer, a contact 12a of the timer is closed and the circuit breaker is interrupted by r energization of a trip coil 10c. The delay time of the timer is determined by considering the allowable time for withstanding short-circuit of the leakage transformer, and the normal operating voltage of relay is determined based on the minimum secondary winding voltage permitting continuous feeding by the leakage transformer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for a sputter ion vacuum pump capable of protecting a leakage transformer for supplying power to the sputter ion vacuum pump.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram of a power supply device for a conventional sputter ion vacuum pump (hereinafter referred to as a sputter ion pump), in which a sputter ion pump 1 has a leakage transformer 4 via a rectifier circuit 3 in a power supply device 2. Is fed from the secondary winding 4 ₂ . The primary winding 4 ₁ of the leakage transformer 4 is connected to the AC power source 5 via the contact 5a of the thermal circuit breaker 5 with a trip coil, and the breaker is a low-voltage circuit connected in series with the primary winding. Having a first heating element 5l for operating the breaker at a level overcurrent value and a second heating element 5h for operating the breaker at a high level overcurrent value, with the first heating element starting a sputter ion pump A manual switch 7 that is sometimes closed is connected in parallel. A voltmeter 8 and an ammeter 9 are connected to the output circuit of the power supply device 1, and the ammeter measures the degree of vacuum of the vacuum device in which the sputter ion pump 1 operates.

By closing the manual switch 7 and then closing the contact 5a of the thermal circuit breaker 5, the leakage transformer 4 is powered and the sputter ion pump 1 is started. For example, when the inside of the electron beam generator of the electron beam irradiation apparatus as a vacuum apparatus is evacuated to vacuum, another sputter ion pump 1 is operated so as to achieve a required high degree of vacuum after rough evacuation by another vacuum pump (not shown). However, when the pump is operating, as shown in the characteristic diagram of FIG. 5, the pump current I shows a characteristic that the pump current I decreases as the pressure P in the vacuum device decreases, that is, as the vacuum degree increases. I greatly changes at the start of starting and in the steady vacuum state.

Considering such a large change in the pump current I, the sputter ion pump 1 is supplied with power from the leakage transformer 4, and as shown in FIG. It has a drooping characteristic that the secondary winding voltage V decreases (the value of the secondary winding current of the leakage transformer and the value of the current of the sputter ion pump through the rectifier circuit, and the secondary winding voltage value and the pump applied voltage value. Are proportional to each other, and therefore, both currents have the same sign I and both voltages have the same sign V.) In the sputter ion pump 1 and the leakage transformer 4, when the manual switch 7 is closed, when the high-level overcurrent state continues, the trip coil operates in response to the second heating element 5h of the circuit breaker, and the contact 5a operates. Open and protect the leakage transformer 4. When the pressure in the vacuum device reaches the steady state region, the manual switch 7 is cut off (contact 5a is opened), and the circuit breaker 5 is connected to the first heating element 5l.
Responds to the occurrence of a low level overcurrent condition.

[0005]

As described above, in the conventional power supply device for the sputter ion pump, when the pump is in a steady state, the manual switch 7 is opened to switch the overcurrent protection level without the operator's hand. It is something that needs to be done. Furthermore, if there is a power failure in the steady state,
When the power failure is restored with the circuit breaker 5 (the contact 5a of the circuit breaker 5 still being turned on), the sputter ion pump is restarted at the overcurrent protection level in the steady state due to the manual switch 7 being opened, which is unnecessary. In some cases, the circuit breaker 5 operates and the pump cannot return to the operating state.

As a power supply for the sputter ion pump 1, considering that the pump current I changes greatly,
Power is supplied from the leakage transformer 4 which has a drooping characteristic in which the voltage greatly decreases when the current increases, but usually the pump current is large at the beginning of the sputter ion pump, and the transformer is almost short-circuited, and the maximum pump current is reached. The value is suppressed by almost the short circuit current Is of the transformer. In this respect, the protection of the leakage transformer 4 at the time of startup is protected by the circuit breaker 5
Even if the overcurrent protection level is set, it will be limited by the characteristics of the leakage transformer. Then, in order to downsize the power supply device, a small leakage transformer 4 is used, but when the degree of vacuum at the start of starting the sputter ion pump 1 is poor, the leakage transformer is close to a short circuit. The operating time will be longer and the transformer will overheat. Therefore,
When the state in which the pump current I does not decrease continues, the operator temporarily shuts off the circuit breaker 5, waits for the transformer to cool, and then restarts the transformer.

According to the present invention, it is not necessary to switch the overcurrent protection setting level between when the sputter ion pump is started and when it is in a steady state, and it is possible to protect the transformer even when the leakage transformer is downsized. An object of the present invention is to provide a power supply device for a sputter ion pump that can be used.

[0008]

The present invention relates to a power supply device for a sputter ion pump, which has a primary winding connected to an AC power source through a circuit breaker and a secondary winding for supplying power to the sputter ion pump. A transformer, a meter relay that responds to the applied voltage of the vacuum pump, a timer connected in series with a normally closed contact of the meter relay, and a trip coil of the circuit breaker that responds to the delay operation of the timer. It is characterized by

[0009]

[Operation] When the sputter ion pump is started, the pump current is large, the voltage applied to the pump is less than the specified voltage at which the meter relay operates, and the timer is energized through the normally closed contact of the meter relay, but the timer expires. The pump current decreases before the delay operation, the pump applied voltage rises above the specified operating voltage of the meter relay, and the startup is completed. When the pump is in a steady state, for example, the pump current increases due to the deterioration of the degree of vacuum, the voltage applied to the pump falls below the specified operating voltage of the meter relay, and if this state continues, the timer operates,
Turn off the circuit breaker by energizing the trip coil.

[0010]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a power supply device for supplying power to a sputter ion pump, and the same reference numerals as those in FIGS. 4 to 6 denote the same parts. The sputter ion pump 1 is supplied with power from the secondary winding 4 ₂ of the leakage transformer 4 via the rectifier circuit 3 in the power supply device 2, and the primary winding 4 ₁ of the same transformer has the trip coil equipped circuit breaker 10. It is connected to the AC power supply 6 via the contact 10a. The output circuit of the power supply device 2 is provided with a meter relay 11 that responds to the voltage applied to the pump and an ammeter 9 that monitors the degree of vacuum from the pump current I.

A timer 12 is provided in parallel with the primary winding 4 ₁ of the leakage transformer 4 via a normally closed contact 11b of a meter relay 11.
(T), and the trip coil 10c of the circuit breaker 10 is connected via the delay operation contact 12a of the timer.

Turn on the circuit breaker 10 (contact 10
By closing a), the sputter ion pump 1 is powered by the leakage transformer 4 and starts. The relationship between the secondary winding voltage of the leakage transformer 4 and the secondary winding voltage, that is, the pump current I which is the output of the rectifier circuit 2 and the pump applied voltage V has a drooping characteristic shown in FIG. The pump current I at the start of the pump is large, and the leakage transformer is almost in a short-circuit state. As shown in FIG. 2B, the transformer has a short-circuit tolerance time ts of about 2 minutes under the short-circuit current Is, for example. The one having is used.

With the start of operation of the sputter ion pump 1, the pressure of the vacuum device and hence the pump current I decreases,
As shown in FIG. 3A, the pump applied voltage V increases. The meter relay 11 that responds to the pump-applied voltage V is the voltage Va in the operation characteristic diagram of the leakage transformer of FIG.
For example, a secondary winding current I that a leakage transformer can supply continuously
Normally closed contact 1 of the relay until the specified operating voltage Va, which is equal to or higher than the minimum secondary winding voltage capable of continuously supplying power corresponding to c, is reached.
1b is closed, and the timer 12 is in the energized state. However, the timer is set to the short-circuit tolerance time ts of the leakage transformer 4, for example, after 2 minutes of energization, the timer is timed up and the delay operation is performed.
Make a close.

Therefore, the operation of the sputter ion pump 1 causes the pressure of the vacuum device to drop sufficiently, and the timer 12
The pump applied voltage V is the specified operating voltage V
When the value becomes a or more, the meter relay 11 operates, and FIG.
As shown in (b), the normally closed contact 11b opens (off),
The energization of the timer is released, and the power supply device 2 enters the steady operation state from the startup operation.

Before starting the sputter ion pump 1, another vacuum pump performs a vacuum evacuation called rough evacuation. If the ultimate vacuum at that time is not good, the pump applied voltage reaches the specified operating voltage Va of the meter relay 11. Before the timer 12 has timed up, the delay operation contact 12a is closed, the trip coil 10c of the circuit breaker 10 is operated,
Breaker breaker, contact 10a is opened. As a result, the continuation of the overload state of the leakage transformer 3 is protected. At this time, wait about 30 seconds for the leakage transformer 4 to cool,
The breaker is turned on again to restart the sputter ion pump 1.

During steady operation, the degree of vacuum of the vacuum device deteriorates for some reason, and the pump current I increases, causing the pump applied voltage V to fall below the specified operating voltage Va of the meter relay 11, as shown in FIG. 3 (b). The normally closed contact 11b is closed (on) and the timer 12 is energized. When the pump applied voltage continues to decrease and the timer 12 times up after the delay time Td and the contact 12a closes as shown in FIG. 3C, the trip coil 10c of the circuit breaker 10 is energized (on). The contact 10a opens, shuts off the power supply to the leakage transformer 4, and interrupts and protects the transformer from continuing the overload condition.

The protection mode associated with the reduction of the pump applied voltage V during the steady operation also works in the case of a failure in the power supply device 2. For example, if there is a failure of the rectifying element in the rectifier circuit 3, an internal failure of the leakage transformer 4, deterioration of the insulation of the wiring in the power supply device 2, etc., the pump applied voltage V appears to decrease.
When the lowered state continues, the circuit breaker 10 is shut off to protect the power supply device. According to the detection of the drop in the voltage V applied to the pump, the failure of the part which cannot be detected by the heating element (5l, 5h) of the circuit breaker (5) monitoring the primary winding current of the leakage transformer in the conventional power supply device. , For example, the failure of the AC power supply side part from the heating element,
Insulation deterioration status can be detected and meter relay 1
In the drooping characteristic of the leakage transformer 4 having the prescribed operating voltage Va of 1 or less, the voltage greatly changes with the increase of the current, so that the above-mentioned failure state can be detected early by the decrease of the pump applied voltage. It is possible to prevent the damage from spreading.

If a power failure occurs during steady operation and the power failure is restored while the contact 10a of the circuit breaker 10 remains closed, if the pump applied voltage V is equal to or higher than the specified operating voltage Va of the meter relay 11, then steady operation is performed. The operating state is entered, and if the voltage is equal to or lower than the specified operating voltage, the timer 12 is energized to enter the starting operation mode.

[0019]

Since the present invention is configured as described above, it is not necessary to switch overcurrent protection levels as in the conventional power supply device, which saves operator's trouble and leakage caused by forgetting to switch. It is possible to prevent the transformer from overheating and continuing to be overloaded.

Furthermore, when a power failure occurs during the operation of the sputter ion pump and the power is restored thereafter, the situation in which the sputter ion pump cannot be operated unlike the conventional apparatus does not occur, and depending on the degree of vacuum when the power is restored, The pump operation can be automatically restarted in the steady operation mode or the startup operation mode.

By detecting the voltage applied to the pump, a failure inside the power supply device, for example, a failure of the leakage transformer,
The failure of the rectifying element in the rectifying circuit and the insulation deterioration of the wiring can be detected at an early stage, and the spread of damage can be prevented.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of operating characteristics of a leakage transformer.

FIG. 3 is an explanatory diagram of a protection operation of the embodiment.

FIG. 4 is a configuration diagram of a power supply device for a conventional sputter ion pump.

FIG. 5 is a pressure-current characteristic diagram of a sputter ion pump.

FIG. 6 is a characteristic diagram of a leakage transformer.

[Explanation of symbols]

 1 Sputter Ion Pump 2 Power Supply Device 3 Rectifier Circuit 4 Leakage Transformer 9 Ammeter 10 Circuit Breaker 10c Trip Coil 11 Meter Relay 11b Meter Relay Normally Closed Contact 12 Timer

Claims (1)

[Claims] 1. A leaky transformer having a primary winding connected to an AC power source via a circuit breaker and a secondary winding for supplying power to a sputter ion vacuum pump, and a meter relay responsive to an applied voltage of the vacuum pump. And a timer connected in series with a normally closed contact of the meter relay, and a trip coil of the circuit breaker that responds to a delay operation of the timer, and a power supply device for a sputter ion vacuum pump.