Use Of The 6V6180 Ammeter Calibrator Group{0778} Caterpillar

The 6V6180 Ammeter Calibrator Group (1) can be used to check the accuracy of and calibrate (adjust) Caterpillar Clamp-on DC Ammeters, including the new 6V4910 AC/DC Clamp-on Ammeter. The 6V6180 Ammeter Calibration Group is a replacement for the former 5P8608 Calibration Group, which has been cancelled. The internal circuits of both calibrators are the same. Two separate calibration coils are part of the 6V6180 Calibrator Group. In addition to the original 5P8609 Coil (2), a new 6V6124 Coil (3) is now included to permit the calibrator group to be used with the new 6V4910 AC/DC Ammeter.

The following chart gives the correct coil to be used with each Caterpillar Ammeter.

NOTE: Do not use the 6V6124 Calibration Coil with the 2P5540 or 5P969 Ammeters or the 5P300 Electrical Tester or the results will not be correct. Also, the 5P8609 Calibration Coil cannot be used with the 6V4910 Ammeter because it will not fit in the aperture of the Ammeter.

6V6180 Ammeter Calibrator Specifications

Input Voltage Range: 0 to 12 Volts DC at 2 Amps maximum with 5P8609 Coil.

0 to 18 Volts DC at 2 Amps maximum with 6V6124 Coil.

Input Voltage Source: 0 to 18 Volts DC with power supply of 2 Amperes capacity or 12V Automotive Battery.

Operation Temperature Range: 0°C to 50°C (32°F to 122°F).

Size: 313 mm x 205 mm x 98 mm (12.3" x 8.1" x 3.9").

Weight: 6V6180 Ammeter Calibrator Group 1.9 kg. (4 lbs. 4 oz.)

Accuracy: .55% of reading - maximum error over operation temperature range.

± .22% of reading - typical error over operation temperature range.

± .1% of reading - typical error at 25°C (77°F).

Output Current: Calibration current up to 600 Amperes by selection in six different ranges.

Voltmeter Needed: 6V3030 Digital Multimeter or equivalent.

5P8609 Coil: 308 turns of 20 gauge magnet wire. Resistance 3 Ohms nominal. 95 mm (3.75") outside coil diameter sized for 25 mm (1.0") minimum diameter apertures on 2P5540, 5P969 and 5P300 Ammeters.

6V6124 Coil: 300 turns of 22 gauge magnet wire. Resistance 6 Ohms nominal. 127 mm (5.0") outside coil diameter sized for 19 mm (.75") minimum diameter aperture on 6V4910 AC/DC Ammeter.

Connections And Controls

(1) PUSH TO CALIBRATE button: Momentary contact switch used to activate current flow through the Calibration Coil.

(2) VOLTMETER jacks: Connect to digital Voltmeter test leads to read calibration current. Connect red + (positive) terminal to meter + (positive) and - (negative) terminal to meter - (negative).

(3) 12 VDC Input Voltage terminals: Connect the calibrator to input Voltage source of 12 or 18 Volts DC at 2 Amps maximum. Connect red terminal to + (positive) and black terminal to - (negative) source terminals.

(4) COIL terminals: Double banana jacks for connection to calibration coil. Connect red coil plug to red + (positive) jack, and black coil plug to black - (negative) jack.

(5) CURRENT SELECTOR switch: Six position switch is used for selection of different calibration current levels when a fixed input Voltage source is being used.

Necessary Equipment For Operation Of The Calibrator

In addition to the 6V6180 or 5P8608 Ammeter Calibration Group, the following equipment is necessary for calibration of Ammeters.

(1) A variable DC power supply, 18 Volts maximum at 2 Amperes or a 12 Volt, 2 Ampere battery.

(2) 18 gauge or larger, insulated copper wire leads (two necessary).

(3) 6V3030 Digital Multimeter .25% minimum accuracy, with standard test leads or equivalent.

Operation Instructions For Accuracy Check Of 2P5540, 5P969 And 5P300 Ammeters

See the accuracy check and calibration instructions given in each specific Special Instruction on these Ammeters. Also see the following procedure for additional information.

(1) Use the 6V6180 or 5P8608 Ammeter Calibrator and 5P8609 Calibration Coil, and the equipment listed on page 8. The maximum Voltage necessary for this test is 12 Volts DC.

(2) Connect the 12 Volt power supply (4) or battery to 12 Volt DC terminal (5) on the calibrator with 18 gauge or larger wire. Connect the + (positive) supply lead to + (positive) and the - (negative) supply lead to - (negative). If a power supply is used instead of a battery, turn it on and set the output to 12 Volts.

NOTE: The power supply must not be more than 12 Volts when the 5P8609 Calibration Coil is used.

(3) Connect 6V3030 Digital Multimeter (6) to VOLTMETER terminals (7) with the standard meter test leads. Set the multimeter to the 20 VDC range.

(4) Connect 5P8609 Calibration Coil (8) leads into COIL jacks (9). Put the red plug in + (positive) and the black plug in - (negative). Use a separate power source to power the ammeter to be tested.

(5) Put Ammeter probe (10) over the coil so the arrow on the Ammeter is in the same direction as the arrow on the coil. The arrow on the coil shows the direction of current flow through the coil. Make sure the jaws of the Ammeter are closed tight and the coil is free to move in the aperture of the probe.

NOTE: Keep the calibration coil straight out from the end of the Ammeter as shown, or the calibration results will not be correct.

(6) Turn CURRENT SELECTOR knob (11) to the number one position. Press PUSH TO CALIBRATE switch (12) and make a comparison between the reading on the Ammeter and the reading on the digital multimeter. The multimeter shows the actual calibration current. One Volt on the multimeter is the same as 100 Amps of calibration current. On the 20 VDC scale of the 6V3030 Digital Multimeter, current can be read directly in Amps, except that the position of the decimal point is not correct.

NOTE: Do not hold down PUSH TO CALIBRATE button (12) too long or the coil and calibrator will heat up.

(7) Check the Ammeter accuracy at different current levels by turning CURRENT SELECTOR knob (11) to other positions. If a variable power supply is being used for power to the calibrator, the output power Voltage can be changed to give different current levels.

Operation Instructions For Accuracy Check Of The 6V4910 AC/DC Clamp-On Ammeter

See the accuracy check and calibration instruction in Special Instruction Form SEHS8030, "USING THE 6V4910 AC/DC CLAMP-ON AMMETER". Use that procedure, but make all changes given in the following procedures.

(1) In addition to the 6V6180 or 5P8608 Ammeter Calibrator and 6V6124 Calibration Coil, use the equipment listed on page 8.

(2) Connect the 12 or 18 Volt power supply or 12 Volt battery (13) to 12 Volt DC terminals (14) on the calibrator with 18 gauge or larger wire. Connect the + (positive) supply lead to + (positive) and the - (negative) supply lead to - (negative). If a power supply is used instead of a battery, turn it on and set the output Voltage at 18 Volts (12 Volts can be used if 18 Volts is not available, but maximum calibration current will be lower).

(3) Connect 6V3030 Digital Multimeter (15) to VOLTMETER terminals (16) using the meter test leads. Set the meter to the 20 VDC range.

(4) Connect 6V6124 Calibration Coil (17) leads into coil jack (18); red plug in the + (positive) and the black plug in the - (negative).

(5) Open the jaws of the Ammeter and put the 6V6124 Calibration Coil in the aperture of the Ammeter. Make sure the arrow on the coil is in the same direction as the arrow on the Ammeter. Move the coil slightly to be sure it is loose in the aperture and the jaws are closed tight.

(6)

NOTE: The 6V6124 Calibration Coil is accurate when used in one position only. It must be held straight out from the end of the ammeter as shown. Any change from this position will cause an error in the readings. To help keep the coil in this position during test, put the coil on the CURRENT SELECTOR switch knob with the Ammeter in the location as shown.

(7) Turn CURRENT SELECTOR knob (19) to the number one position for the lowest current setting. Press PUSH TO CALIBRATE switch (20) and make a comparison between the Ammeter reading and the reading on the 6V3030 Digital Multimeter. The multimeter will show the actual calibration current. On the 20 VDC scale of the 6V3030 Digital Multimeter, current can be read directly in Amps, except the decimal point is not in the correct location.

NOTE: Do not hold down PUSH TO CALIBRATE button (20) too long or the coil and calibrator will heat up.

(8) Check the Ammeter accuracy at different current levels by turning CURRENT SELECTOR knob (19) to other positions. For calibration of the 6V4910 Ammeter, a calibration current of exactly 400 Amps^* is necessary. To get this current, adjust the calibrator power supply to 12.0 Volts and use CURRENT SELECTOR position number six. Do not use the Voltages of 8.5 and 14 Volts given on page 13 of Special Instruction Form SEHS8030, "USING THE 6V4910 AC/DC CLAMP-ON AMMETER".

NOTE: Do not use more than 18 Volts DC with the 6V6124 Calibration Coil, or the results will not be correct.

NOTE: The 6V4910 is adjusted for zero error at this 400 Amp. point only.

Circuit Description And Wiring Diagram

(1) The Ammeter calibrator, with the calibration coil, is a current multiplier circuit. When an external power supply is connected to the 12 Volt DC terminals, current flows through the circuit when a coil is plugged in and the PUSH TO CALIBRATE button S2 is depressed. Because the coil has approximately 300 turns of wire, the magnetic field around the coil is the same as that of a single wire carrying 300 times the current flowing in the calibrator circuit and coil. Since clamp-on Ammeters measure current by sensing the magnetic field, they indicate a value 300 times greater than that being supplied by the calibrator power supply. This permits the Ammeter to be checked over a wide current range with only a small power supply. The current flowing through the calibrator circuit passes through resistor R6. This resistor is of a size that has a 1 Volt drop across it for every 100 Amps of calibration current. Therefore, actual calibration current can be found by measuring the Voltage across R6 resistor with a digital multimeter. The CURRENT SELECTOR switch S1 switches different values of resistance (R1-R5) into the circuit to change the amount of current. This permits six different calibration currents to be available from a fixed Voltage supply.

Parts List And Location

REFERENCE DESCRIPTION

R1 Resistor, Carbon, 110 Ohms, 1W, 5%R2 Resistor, Carbon, 15 Ohms, 2W, 5%R3 Resistor, Ohmite Brown Devil No. 2738R4 Resistor, Ohmite Brown Devil No. 2844R5 Resistor, Ohmite Brown Devil No. 1503R6 Resistor, Dale RH25, 0.1% No. 7724S1 Switch, SP6P Rotary, Centralab No. 1401S2 Switch, SPST Momentary, Grayhill No. 4001 or 1411BP1 Binding Post, Red, H. H. Smith No. 897 or 269RBBP2 Binding Post, Black, H. H. Smith No. 897 or 269RBJ1 Jack, Banana, Red, H. H. Smith No. 219-102J2 Jack, Banana, Black, H. H. Smith No. 219-103J3 Jack, Phone Tip, Red, H. H. Smith No. 1501-102J4 Jack, Phone Tip, Black, H. H. Smith No. 1501-103Lid Label Form SEHS8103Case 6V3073

Repair Of 5P8609 And 6V6124 Calibration Coils

The calibration coils can be checked for accuracy using the 6V3030 Digital Multimeter. Measure the resistance between the two leads coming from the coil. They plug directly into the V-Ohms and COM jacks on the 6V3030 Digital Multimeter. With the FUNCTION/RANGE switch on the multimeter set at 200 Ohms, the coil resistance can be read on the digital display. The 5P8609 Coil should read approximately 3 Ohms, and the 6V6124 Coil should read approximately 6 Ohms. If the coil measures OL (infinite Ohms) it is open, and if it measures 0 Ohms it has a short. If it has a short or is open, it cannot be repaired unless the problem is in the leads from the coil.

Parts And Repair Service For The Ammeter Calibrator

If the calibrator does not operate correctly, it should be returned to the manufacturer for service. Send a letter with the unit, including a description of the problem and the date of purchase from Caterpillar. Calibrators less than one year old will be repaired under warranty, except for abuse. The cost of out-of-warranty repairs will be charged to the owner. Repair service for the calibrators is available from: