scispace - formally typeset
Search or ask a question
Author

Raymond O. D. Whitt

Bio: Raymond O. D. Whitt is an academic researcher from Westinghouse Electric. The author has contributed to research in topics: Circuit breaker & Distribution board. The author has an hindex of 3, co-authored 4 publications receiving 52 citations.

Papers
More filters
Patent
22 Aug 1979
TL;DR: In this article, an undervoltage relay device for a circuit breaker system with a time delay feature was proposed. But the relay was not considered. And the relay conditions were not specified.
Abstract: This concerns an undervoltage relay device for a circuit breaker system with a time delay feature. Two lines of the electrical system to be protected are monitored by a transformer. The output of which is rectified and provided to a capacitive element which, among other things, filters the signal. The capacitive element may comprise a single capacitor or combination of capacitors. The combination chosen is the function of the amount of time delay desired. If the voltage across the monitor lines drops below a predetermined value, the voltage level across the capacitive element begins to drop accordingly. This decreasing voltage signal is provided by way of a voltage divider to one input terminal of a comparator. The other input terminal of which is maintained at a reference voltage. When the signal voltage drops below the reference voltage, the comparator shift state thus causing an undervoltage relay coil to be deenergized. The armature of the undervoltage relay coil is spring biased so that upon deenergization the armature moves under the influence of the bias thus tripping the circuit breaker. The capacitive element additionally supplies the voltage for the relay coil. The discharge path for the capacitive element is deliberately chosen so that sufficient voltage will be supplied to the relay coil to keep it energized during the time out period of the time delay element, even though the voltage across the lines has dropped to a lower value. The time out is a function of the capacitance of the capacitive element and the resistance of the discharge path. The output of the previously described comparator element is feedback to another comparator element which controls one of the resistive elements of the previously described voltage divider. When the output of the first comparator element changes states, the second comparator element acts in such a way as to change the effect of the resistive element in the voltage divider path thus latching the first comparator into its last obtained state. Another feature is a light emitting diode which is connected in series with the undervoltage relay coil and which extinquishes when the undervoltage relay coil is deenergized, thus providing a positive indication that an undervoltage relay condition exists. Still another feature includes a memory means which extinquishes when the undervoltage relay condition exists and which remains in a disposition of non-illumination. Even if the undervoltage relay condition disappears to provide an indication to an operator that an undervoltage relay condition had occurred previously.

29 citations

Patent
19 Feb 1988
TL;DR: In this article, a circuit interrupter includes a circuit arrangement for sampling a conditioned current value and determining operating characteristics related to the current flow through an electrical circuit, which is used for comparing the operating characteristics to preselectable tripping parameters and for initiating a trip condition when an operating characteristic exceeds a corresponding tripping parameter.
Abstract: A circuit interrupter includes a circuit arrangement for sampling a conditioned current value and determining operating characteristics related to the current flow through an electrical circuit. Also included is a circuit arrangement for comparing the operating characteristics to preselectable tripping parameters and for initiating a trip condition when an operating characteristic exceeds a corresponding tripping parameter. Additionally, a circuit arrangement for initiating a hardware override trip condition using a minimum number of components upon sensing an override signal, is also included; the override signal representing a limit selectable from a range of values.

16 citations

Journal ArticleDOI
TL;DR: This paper will review the various methods of detecting ground faults using static devices and describe some of the equipment available for these applications.
Abstract: Grounded and ungrounded systems are in general use in both commercial and industrial distribution systems. Proponents of each type of system have established valid points to defend their position. This paper briefly identifies the types of systems in use in each category and lists some of the main advantages and disadvantages of each. With the advent of higher voltage levels in our low-voltage distribution systems and the trend towards solidly grounded systems, problems resulting from the lack of proper ground fault protective devices have caused some severe equipment burndowns. The need for adequate protection has been recognized by the 1971 National Electric Code. This recognition is being complemented by Underwriters' Laboratories with the introduction of appropriate standards. With the passing of the Occupational Safety and Health Act of 1970, more emphasis than ever before will be placed on adherence to the preceding code and standards. This paper will review the various methods of detecting ground faults using static devices and describe some of the equipment available for these applications.

5 citations

Journal ArticleDOI
TL;DR: The first application of instantaneous trip circuit breakers (without time delay) was allowed by the National Electric Code (NEC) as discussed by the authors, provided the pickup can be adjusted above 700 percent to a maximum of 1300 percent of the motor full-load ampere rating.
Abstract: Over the years, various approaches including both thermal magnetic breakers and several types of fusible devices have been used in motor circuit protection schemes with acceptable results. Evidence reported in the trade magazines indicated that the level of protection from these types of devices was not totally effective. For the first time, with the printing of the 1968 National Electric Code, the application of instantaneous trip circuit breakers (without time delay) was allowed provided the pickup could be adjusted above 700 percent to a maximum of 1300 percent of the motor full-load ampere rating. After extensive testing the first product complying with these requirements was introduced to the market in 1969. Experience in motor failures indicates that most faults occur at relatively low levels of fault current just above lock rotor values rather than at higher levels. With rapid clearing of faults in the low-level range such as can be accomplished with the use of instantaneous trip circuit breakers, extensive damage to motors as well as to control equipment can be greatly reduced. By combining low-level protection obtained with the high interrupting capabilities of specially designed current limiters, a full range of coordinated protection is available for both high-and low-level faults.

2 citations


Cited by
More filters
Patent
13 Feb 1987
TL;DR: An information recording medium such as a magneto-optical recording medium is disclosed in this article, where the medium comprises two pieces of recording elements each element comprises a support and a recording layer provided on a part of one surface of the support.
Abstract: An information recording medium such as a magneto-optical recording medium is disclosed The medium comprises two pieces of recording elements Each element comprises a support and a recording layer provided on a part of one surface of the support The two pieces of the elements adhere to each other by a non-corrosion-causing adhesive provided on a part of said surface where a recording layer is provided and a fast-hardening adhesive provided on a part of the surface where no recording layer is provided The time required to adhere the two pieces of the elements can be considerably decreased and the corrosion of the recording layer by the adhesive can be avoided

96 citations

Patent
08 Feb 1990
TL;DR: In this paper, an electronic circuit breaker is provided to an ECC, which is of the type that generates trip signals by accumulating squares of power line current samples and thresholds the accumulation results, and the threshold detector result is checked for two consecutive overcurrent indications before an instantaneous trip signal is generated.
Abstract: Instantaneous trip capability is provided to an electronic circuit breaker, which is of the type that generates trip signals by accumulating squares of power line current samples and thresholds the accumulation results Samples of power line current are taken directly from the current transformer and analog-to-digital converter cascade generating them The analog-to-digital converter is of an oversampling type, using a delta-sigma modulator The samples are threshold detected against a prescribed threshold value without previous squaring, integration and detection The threshold detector result is checked for two consecutive overcurrent indications before an instantaneous trip signal is generated

87 citations

Patent
13 Jun 1988
TL;DR: An electric circuit breaker for protecting an electric circuit of an electrical installation of a building is of such a construction that a substantial proportion of its components are standard for the preferred current ratings of the breaker and that some components having a limited useful life can be readily replaced.
Abstract: An electric circuit breaker for protecting an electric circuit of an electrical installation of a building is of such a construction that a substantial proportion of its components are standard for the preferred current ratings of the breaker and that some components having a limited useful life can be readily replaced. The circuit breaker comprises a switching unit with a moulded case housing, fixed and movable contacts, a tripping mechanism and a manually operable dolly switch; an over-current release unit having a moulded case, separately formed with respect to the case of the switching unit, housing an electromagnetic device operatively mechanically coupled to the tripping mechanism and adapted to be electrically interconnected in a power circuit independent of the power circuit to be protected and a current sensor for continuously providing an output signal which is a function of the current flowing through the circuit to be protected, the switching and over-current release units being so detachably electrically connected that current which will flow through the circuit to be protected will flow through the switching unit; and, electrically connected to the current sensor, a microprocessor. The microprocessor can be so programmed that, in the event of a short circuit or sustained overload, a current is caused to flow through the independent power circuit to operate the electromagnetic device and thereby initiate operation of the tripping mechanism of the switching unit.

80 citations

Patent
29 Nov 1994
TL;DR: In this paper, an electrical apparatus (100) line actuator (102), such as a voltage regulator or circuit breaker, has resident therein a personality module, electronically reconfigurable memory device (126) which stores actuator operational information, such as specifications (132), historical and maintenance information.
Abstract: An electrical apparatus (100) line actuator (102), such as a voltage regulator or circuit breaker, has resident therein a personality module, electronically reconfigurable memory device (126) which stores actuator operational information, such as specifications (132), historical and maintenance information. An apparatus controller (106) communicates with the personality module (126) and can change the operational information stored therein. If either or both of the controller (106) and actuator (102) is replaced at a site, the controller (106) of the replacement apparatus configuration (100) can read the operational information stored in the personality module (126) and adapt its operational interaction with the actuator (102) in conformance with the information.

75 citations

Patent
24 Aug 1990
TL;DR: A processor-based tripping system using a precise three phase current detection circuit using a minimal number of components is described in this article, where a set of current sensors are situated adjacent the current path to sense respective phases of current therein.
Abstract: A processor-based tripping system uses a precise three phase current detection circuit using a minimal number of components. A set of current sensors is situated adjacent the current path to sense respective phases of current therein. The current sensors provide respective current signals therefrom which are fed to a ground fault transformer. The ground fault transformer includes input inductors connected to respective ones of the current sensors such that current flowing through each respective current sensor also flows through one of the input inductors. An output inductor in the ground fault transformer is coupled with the input inductors for adding the current signals from the current sensors and for producing an output current signal in the presence of a ground fault. The output current signal is then rectified to provide a rectified signal corresponding to the output current. The processor receives the rectified signal to detect the ground fault in the three phase current path and provides a trip signal to a solenoid to break the current path. The ground fault transformer also includes a test input inductor for receiving an external AC signal to simulate a ground fault.

64 citations