NORMAL-CONDITION-OFF-TYPE PROTECTION ELEMENT AND CONTROL UNIT HAVING THE NORMAL-CONDITION-OFF-TYPE PROTECTION ELEMENT
First Claim
1. A control unit for controlling driving of a motor that revolves and drives a heat exchanger cooling fan of a cooling system using a cooling medium and a heat exchanger, the control unit including at least a switching element for controlling the driving of the motor, and a controller for transmitting a control signal to the switching element, the control unit comprising:
- a normal-condition-OFF-type protection element having a first terminal connected to one of two wires connected respectively to a positive and a negative pole connected to the motor, and a second terminal directly connected to a ground wire without being connected to the other of the wires connected to the positive and the negative poles; and
short-circuit means, arranged inside the normal-condition-OFF-type protection element, for short-circuiting the first terminal and the second terminal when an overheating caused by the switching element attains a predetermined temperature or higher, whereinthe short-circuit means short-circuits the first terminal and the second terminal when the overheating caused by the switching element attains the predetermined temperature or higher, whereby an electric current flowing into the switching element is decreased, and the control unit is shifted to a temperature range safe from the overheating caused by the switching element without stopping the cooling system.
1 Assignment
0 Petitions
Accused Products
Abstract
A first terminal of a protection element of a control unit is connected to a wire between a motor and a switching element, and a second terminal is directly connected to a ground-side wire shared by a controller and the switching element. The protection element has a normal-condition-OFF-type switch including a movable contact and a fixed contact. When an overheating caused by the switching element attains a predetermined temperature or higher, the movable contact and the fixed contact are closed to short-circuit the first terminal and the second terminal, and an electric current is branched to the protection element side to reduce an electric current flowing into the switching element, and the control unit is shifted to a temperature range safe from the overheating caused by the switching element without stopping a cooling system.
16 Citations
17 Claims
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1. A control unit for controlling driving of a motor that revolves and drives a heat exchanger cooling fan of a cooling system using a cooling medium and a heat exchanger, the control unit including at least a switching element for controlling the driving of the motor, and a controller for transmitting a control signal to the switching element, the control unit comprising:
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a normal-condition-OFF-type protection element having a first terminal connected to one of two wires connected respectively to a positive and a negative pole connected to the motor, and a second terminal directly connected to a ground wire without being connected to the other of the wires connected to the positive and the negative poles; and short-circuit means, arranged inside the normal-condition-OFF-type protection element, for short-circuiting the first terminal and the second terminal when an overheating caused by the switching element attains a predetermined temperature or higher, wherein the short-circuit means short-circuits the first terminal and the second terminal when the overheating caused by the switching element attains the predetermined temperature or higher, whereby an electric current flowing into the switching element is decreased, and the control unit is shifted to a temperature range safe from the overheating caused by the switching element without stopping the cooling system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 14, 15, 16, 17)
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9. A control unit for controlling driving of a motor that revolves and drives a heat exchanger cooling fan of a cooling system, the control unit including at least a switching element for controlling the driving of the motor, and a controller for transmitting a control signal to the switching element, the control unit comprising:
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a protection element having a first terminal connected to one of both contacts that are open under normal conditions, and a wire connecting the motor and the switching element, a second terminal connected to the other of the contacts and a ground-side wire of the switching element and the controller, and a third terminal connected between the second terminal and a ground terminal of the control unit via an overcurrent interrupt element, wherein when an overheating caused by an anomaly in an internal element occurs, the overheating of the control unit is suppressed by decreasing an electric current flowing into the switching element via short-circuiting between the first terminal and the second terminal, and if a tolerance value is exceeded by heat produced by the electric current, the protection element interrupts between the second terminal and the third terminal to interrupt the control unit from a power supply, and shifts the control unit to a safe temperature range. - View Dependent Claims (10)
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11. A normal-condition-OFF-type protection element recognizing a control circuit for driving and controlling an external circuit as a circuit to be protected, comprising:
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a first terminal, connected to a contact within the element, extending externally to the element in order to be connected to one of two wires connected respectively to a positive and a negative pole of the circuit to be protected; a second terminal, connected to the other of the contacts within the element, extending externally to the element in order to be connected to the other of the wires of the positive and the negative poles; a third terminal to be connected to a ground wire externally to the element; and a temperature fuse, arranged between the second terminal and the third terminal, melting down at a predetermined temperature or higher, wherein the normal-condition-OFF-type protection element becomes a normal-condition-OFF-type by opening the contacts under normal conditions, and protects the circuit to be protected from being damaged due to overheating via a branch of an electric current of the circuit to be protected between the first contact and the second contact by closing the contacts at an anomalous temperature, if the anomalous temperature further increases to the predetermined temperature or higher, the temperature fuse melts to interrupt a current path between the first and the second contacts and the third contact, so that electric currents of the circuit to be protected and the external circuit are interrupted. - View Dependent Claims (12, 13)
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Specification