Since only minute power is required to operate Open-Phase Indication the Knopp Sequence Indicator, there is no
applications Phasing-In Power Circuits After Alterations The most frequent application for the Knopp Phase Sequence Indicator is for phasing-in a power line which has supplied power to motors and plants, and where line alterations are made in the circuit feeding this line. It is necessary to determine the sequence before alteration is made so that the same sequence can be reestablished for the consumer by the line crew after alteration has been made. This will avoid any possibility of damage incident to reversing the consumers' motors and machinery. Connecting Motors and Generators Use of the Knopp Sequence Indicator protects apparatus and enhances service efficiency. By indicating which terminals of a newly installed prevents damage and saves time. Obviously the trial-and-error method is not permissible for direct-connected electric motors which, because of the nature of the machines they drive, cannot be operated in reverse. Furthermore, reversal of a generator's phase rotation when being paralleled would result in a short circuit. Suppose a three-phase motor load is to be connected to a new set of three-phase conductors. Before a change is made, the original power sequence to the load is determined by attaching the Sequence Indicator to the line side of the motor switch. After temporary new connections are made, the line is again energized and the phase sequence checked. If the original sequence is reversed, two of the new conductors can be interchanged to give the original sequence.
The presence of an open circuit in at least one phase of a three-phase supply is indicated by the failure of the Sequence Indicator to rotate when connected to the circuit. Six-Phase Sequence The Indicator can be used to determine the phase order of six-phase circuits by arranging the six terminals into two groups of three, each group having equal voltage between all pairs of terminals and both groups having the same sequence, the two 3-phase triangles should form a hexagon with equal voltage sides. The Knopp Phase Sequence Indicator includes a three-phase induction motor having an aluminum-disc rotor mounted for free rotation on a cushioned glass-hard bearing and having field windings placed at 120 geometrical- degree intervals about the rotor axis. One terminal of each winding is extended beyond the case to a distinctly colored conductor and to a lettered test clip for attachment to one conductor of the tested system; and the second terminal of each winding is connected to one of three contacts of the insulated protector-switch. The protector-switch must be held closed to energize the windings and is so arranged that accidental or even continuous closure of the switch is unlikely. The flexible cable withstands severe handling and is intended for suspending the instrument from the line wires or terminals with the test clips. The free ends of the conductors are shorter than the sheathed portion so that, when the instrument is suspended, a detached clip cannot contact the operator while the switch is closed. Since the cable is anchored in the sealed housing, clockwise rotation of the rotor always means that the phase order of the tested terminals is that of the marks A, B, C, on the clips attached thereto.
need for making tight connections until the correct order has been established. Motor and Generator Terminal Markings It will be obvious that the Knopp Sequence Indicator may be used to correlate definitely the motor and generator conductor markings with the phase sequence of applied or generated voltage. Connections of Polyphase Power-Factor Meters Where instrument transformers are employed for power factor metering, mistakes are easily made in the connections. The phase sequence of the input current for the current coils should be checked for the correct order of attachment, as indicated by the
polyphaser power circuit are to be connected to the sequence-identified motor terminals, it manufacturer's diagrams. The phase sequence eliminates the trial-and-error method and thus of the voltage coils is determined by the
Sequence Indicator.
Reactive-Volt-Ampere Connections When varmeters are being connected in polyphaser circuits, it is necessary to use the correct phase order so as to assure the correct meter indications. The Knopp Indicator furnishes direct and positive means of determining the proper sequence. Two-Phase, 3-Wire Operations The Knopp Sequence Indicator (catalog No. 44030, 3-phase, 3-wire type) will operate satisfactorily on 2-phase, 3-wire systems. However, it should be noted that on such systems the voltage between the outers is 1.4 times the phase voltage. This factor should be taken into consideration when using the Indicator on higher voltage circuits, bearing in mind the voltage rating of the instrument.
CATLALOG NUMBER
LEAD
DIMENSIONS
APPROX. WEIGHT Net Shipping 21 oz. 24oz. 21 oz. 24oz. 20oz. 23 oz. 21 oz. 24oz. 23 oz. 26oz. 22 oz. 25 oz. 21 oz. 24oz.
MODEL
TYPE
FREQUENCY
VOLTAGE
LENTH Diameter Height
3-phase 3-wire 3-phase 3-wire 3-phase 3-wire
25-60*
60-600 24-480 60-600 60-600 60-600 60-600 60-600
36" 36" 26" 36" 72" 50" 36"
44030 K-3 44035 K-6
3-1/4" 1-5/8"
1-5/8" 1-5/8" 1-5/8" 1-5/8" 1-5/8"
3-1/4" 3-1/4" 3-1/4" 3-1/4" 3-1/4"
400
25-60* 25-60* 25-60* 25-60* 25-60*
K-7
N/A N/A N/A N/A N/A
K-7-1 3-phase 3-wire K-7-2 3-phase 3-wire K-7-3 3-phase 3-wire K-7-4 3-phase 3-wire Cordura Carrying Case
3-1/4" 1-5/8"
44050
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