Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
  • H02H7/22—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices
  • H02H7/226—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices for wires or cables, e.g. heating wires
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H5/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection
  • H02H5/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal fluid pressure, liquid level or liquid displacement, e.g. Buchholz relays
  • H02H5/083—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal fluid pressure, liquid level or liquid displacement, e.g. Buchholz relays responsive to the entry or leakage of a liquid into an electrical appliance

Definitions

• the invention relates to electrically operated, in particular portable, devices that work with liquid media or can come into contact, are connected to the fixed power supply network by means of a movable network connection and have an electronic protective device as a leakage protection or to protect the user from an electric shock according to the preamble of the main claim.
• Devices of this type are e.g. Washing machines and dishwashers (DE 25 39 279), submersible pumps - leak protection -, air bubble massage devices (DE 26 31 785), computing devices, hair dryers (EP-A 1831),
• Fan heaters radiation lamps, which are also used in damp rooms - electrical death -.
• the electronic protective device responds to the upper sensor (probes) and switches off the water supply for washing machines and dishwashers, or the mains for two-pole devices for domestic, kitchen and workshop equipment.
• the switch-off takes place by means of a solenoid valve (DE 25 39 279) or by means of a relay (DE 26 31 785, EP-A 1831) or by triggering a fuse switch protected by a fuse (DE 32 08 147).
• the protective device can, however, become dangerously ineffective if there is a wire break in the movable mains connection belonging to the device.
• This wire can be the neutral wire for double isoller devices that only require a two-core power cord. The device is then not operational, but can be switched on and then be live.
• the invention is therefore based on the object to provide extensive intrinsic safety in a device and arrangement of the type described with as little construction or circuitry complexity as possible such that the device is immediately de-energized if the protection fails.
• an intrinsically safe protective device which not only, like other unsecured protective devices, also penetrates e.g. of water in the device housing, the mains voltage is already switched off in the mains plug within a very short period of time - depending on the design of the circuit breaker - irreversibly before the user can come into contact with live parts of the device via the penetrating water, but also the constantly live mains voltage Mains connection cable encircled in the protection up to the mains plug, namely against wire breaks or insulation damage, which are not recognizable under the sheath, but make the protection ineffective.
• a broken wire is noticeable because the Gerfit cannot be put into operation, but the undamaged wire can still be used to supply mains voltage to earth on open parts of the device.
• the heating element of a hair dryer, fan heater or the like lie and lead to accidents, especially since the user will gullible assume that the device is completely dead.
• the shield is used as the signal line of the probe. This arrangement can also be viewed as if the probe was extended beyond the mains connection to the mains plug.
• the integrity of the probe installed in the device housing can be monitored if, according to claim 3, the closed-circuit current loop is guided over the double conductors of the probe.
• the overall protection is obtained according to the invention with a two-core, shielded line, the shielding of which can be loosely beaten, while the known solutions require a four-core line (two current-carrying wires and two signal wires) which is heavier, less flexible and expensive.
• the drawing shows the circuit diagram of the protective device for an electrically operated device 30 with a blower motor 37 and a heating register 38, for example a hairdryer or a fan heater, which is connected via a two-wire shielded mains connection 50 to a mains plug 60, in which the components 6-20 the electronic circuit are housed.
• a blower motor 37 and a heating register 38 for example a hairdryer or a fan heater
• the connector internal network cables 3a, 4a lead via the switch contacts 3, 4 of a two-pole circuit breaker 5 to the terminals 24, 26, to which the wires 21, 23 of the network connection cable 50 are connected.
• the circuit breaker forms a diagonal (between points A and C) of a diode quartet 6 - 9 in series with a diode 12, a resistor 13 and a semiconductor switch, a thyristor 14.
• the resistor 13 forms one with the capacitor 19 connected in parallel with the thyristor Protection against its overhead ignition when the consumers 37, 38 are switched on in the device 30.
• the RC element 15, 20, on which the control electrode of the thyristor 14 is located, serves as protection against short-term mains disturbances.
• a transistor stage 16, 17 is connected between the control electrode and the base of the thyristor 14 (point C). The base of the transistor is connected via a resistor 18 to a third terminal 25, to which the shield 22 of the mains connection line 50 is connected.
• Wires 21, 23 and shield 22 of the power cord are connected in the device 30 to its terminals 31, 32, 33.
• the load circuit of the device runs from the terminals 31, 33 via the internal power lines 34, 35 and the operating switch 36, motor 37 and heating register 38. From the terminal 32, a line leads via the open double line 40, 41 of the probe and one connected between them Resistor 39 and a high-resistance protective resistor 42 on a branching of diodes 10, 11 connected to one another, which are connected between the power lines 34, 35.
• the diodes 8, 9 of the diode quartet in the connector 60 with the diodes 10, 11 in the device form a second diode quartet, in the diagonal of which the series circuit consisting of transistor 16: base resistor 18 shielding 22 probe line 40 resistor 39 probe line 41 - Protection resistor 42 is.
• the pair of diodes 10, 11 in the device 30 and back via the double line 40, 41 with the resistor 39 lying parallel to it leads from the electronic circuit in the mains plug 60 via the wires 21, 23 of the mains connection line 50 (depending on the phase position of the mains change voltage) and the shield 22 of the mains connection to the base resistor 18 of the transistor stage 16, 17 connected as an emitter follower, a quiescent circuit for monitoring the entire arrangement for functionality.
• the diode 12 in the diagonal of the diode quartet 6-9 ensures that at points A, B, C the rippled DC voltage has the same phase position (simultaneous zero crossings).
• the circuit works as follows:
• a low quiescent current of e.g.
• the circuit breaker is expediently designed in such a way that its position is reversible, so that the fault must first be eliminated.
• a switch is e.g. in patent EP-88390.
• the quiescent current rises sharply above a predetermined upper threshold and thus the current in the circuit 16-17 rises so sharply, e.g. to 700 ⁇ A that due to the voltage drop across resistor 17, the voltage at the control electrode of thyristor 14 rises again into the ignition range and the thyristor switches through.
• the thyristor thus ignites and triggers the circuit breaker 5 as soon as the current in the closed-circuit loop drops below a predetermined lower threshold or rises above an upper threshold.
• the loop current falls below the quiescent current threshold to zero.
• Liquid contact due to ingress of water into the device or immersion of the defective connecting line
• Threshold on The advantages of the protective device according to the invention are its low manufacturing costs, its high intrinsic safety and the extensive protection of users of electrical devices in the home and workshop, which are fed via a movable mains connection line, in particular those which are used in wet cells in the living area, in bathing establishments, hospitals (for example hydrotherapy) and the like be used, and in their suitability for electrically triggered circuit breakers of any type. Only the probe and its supply lines are to be provided in the device to be protected.
• the switching elements required for their connection with wires and shielding of the mains connection line can also be accommodated in a watertight cable entry grommet, so that only four connection terminals (two each for the double line of the probe and the mains lines) are required on the device.
• the electronic ignition circuit which can be modified in details compared to the exemplary embodiment, with the isolating switch can be accommodated in a volume of, for example, 20 x 20 x 10 mm, so that the dimensions of the power plug are only slightly larger than usual.

Landscapes

• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Details Of Connecting Devices For Male And Female Coupling (AREA)
• Emergency Protection Circuit Devices (AREA)
• Protection Of Generators And Motors (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6320000

Family Applications (1)

Country Status (4)

Families Citing this family (6)

Family Cites Families (8)

• 1987
  • 1987-02-02 DE DE8701530U patent/DE8701530U1/de not_active Expired
  • 1987-02-02 DE DE19873702970 patent/DE3702970A1/de active Granted
• 1988
  • 1988-01-12 WO PCT/EP1988/000016 patent/WO1988005974A1/de not_active Application Discontinuation
  • 1988-01-12 JP JP63501452A patent/JPH01502714A/ja active Pending
  • 1988-01-12 EP EP19880901409 patent/EP0301055A1/de not_active Withdrawn

Non-Patent Citations (1)

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