摘要:
A current measuring device is protected against electrical surges in the event of the device being open circuit. The device includes a first current transformer, a first connection terminal having connected thereto a first terminal of the first current transformer, a second connection terminal having connected thereto a second terminal of the first current transformer, a protective resistance having a first terminal connected to the second connection terminal, and a load resistance connected between the first and second connection terminals across the terminals of which a voltage is measured from which the current flowing in a circuit passing through the first current transformer is determined. The device also includes a second current transformer connected to the terminals of the protective resistance, and current branch connection structure connected between the first connection terminal and a second terminal of the protective resistance.
摘要:
In order to demagnetize a transformer core (13, 23) a demagnetization device (40) is detachably connected to a primary side (11) of a transformer (10, 20). An alternating signal is fed to the primary side (11) in order to demagnetize the transformer (10, 20).
摘要:
Provided is a plug for use as a disconnector for current transformers. Two types of short circuits are provided in the plug. A first short circuit is used for diverting overvoltages by short-circuiting the electrical contacts in the plug. A second short circuit is provided for short-circuiting electrical contacts in the plug when the plug is not contacted. The short circuits are designed in such a way that the first short circuit is used as a fuse when the second short circuit fails.
摘要:
The invention relates to a docking module (22) for a current transformer (10) comprising:an electronic circuit (12) andat least one electric connecting element (28.3) for electrically coupling the circuit (12) to the current transformer (10) and for docking the docking module (22) onto the current transformer (10).
摘要:
Phase angle error and ratio error correction is provided in a current transformer by a bucking voltage opposite in phase to the voltage drop across the burden resistor and inherent winding resistance.
摘要:
The present invention provides a direct-current current transformer, or DCCT, yielding bandwidth from DC to several MHz. The DCCT according to this invention is a simple, open-loop, device in which flux densities occur at very low levels, avoiding difficulties occasioned by core saturation.
摘要:
A current sensor has one signal interface channel including a transformer having a primary winding, a secondary winding and a feedback winding. A magnetic core magnetically couples the primary winding, the secondary winding and the feedback winding. The current sensor further includes a feedback generating circuit responsive to an AC signal in the secondary winding for generating a feedback signal having a continuous polarity supplied to the feedback winding. The feedback signal being effective for maintaining a flux in the magnetic core substantially near zero. The feedback generating circuit is made up of an operational amplifier, such as an amplifier having first and second differential input ports and first and second differential output ports, and a switching assembly designed to generate a compensating AC signal from a DC offset voltage. The compensating AC signal is conveniently coupled to the operational amplifier through the magnetic core.
摘要:
Current transforming apparatus comprising a current transformer and means for developing a current substantially expressed by a.multidot.I.sub.2, wherein I.sub.2 denotes the secondary current of the current transformer. Impedance means is connected in series to a load of the current transformer and has an impedance (Z.sub.2 +Z.sub.L)/(a-1), wherein Z.sub.2 is the secondary leakage impedance of the current transformer and Z.sub.L is an impedance of the load. A current-voltage converter may be employed as the load of the current transformer.
摘要:
The disclosure describes an improved apparatus for measuring the flow of current through a conductor by means of a Hall generator. The Hall generator is biased by a constant current source employing feedback. In order to increase the accuracy of the current measurement, operational amplifiers having inputs which float in relationship to the power supply operating the amplifiers are used to amplify the Hall generator output voltage and to drive a meter. The current measuring apparatus can be used to detect defects in a vehicular alternator by measuring the fluctuating components of the alternator output current. The magnetic field generated by the current to be measured is concentrated in the area of the Hall generator by means of a unique hollow, cylindrical, coiled strip of metal made from nickel, molybdenum and iron. The apparatus includes a regulator in which the voltage drop is so low that a 3.25 volt regulated supply can be maintained from a poorly-charged 6-volt battery.
摘要:
The current transformer system that is the present invention allows for surveillance of an electronic grid at electrical power generating stations, at individual operational substations and in electric power distribution for electric network and grid measurement, protection, and control ranging from very low currents to high current magnitudes. The reception and relay of information from the CT primary circuit is sensed and transmitted by a primary electronic circuitry, digitized, converted to a fiber optic mode, transmitted to a secondary electronic circuit, processed and converted to a digital output and transmitted to various monitoring and recording devices.