MAJOR TECH MT790 Three Phase Power Clamp Meter Instruction Manual

MAJOR TECH MT790 Three- Phase Power Clamp Meter

OVERVIEW

This Operating Manual covers information on safety and cautions. Please read the relevant information carefully and observe all the Warnings and Notes strictly.

WARNING
To avoid electric shock or personal injury, read the “Safety Information” and “Rules for Safe Operation” carefully before using the Meter. This clamp is a three-phase intelligent handheld digital power clamp meter (hereafter referred to as “the Meter”) which has both the features of a digital current meter and also power measurement meter. The Meter can measure Voltage, Current, Active Power, Apparent Power, Reactive Power, Power Factor, Phase Angle, Frequency, Active Energy and etc.

UNPACKING INSPECTION
Open the package case and take out the Meter. Check the following items carefully to see if there are any missing or damaged parts:

In the event you find any missing or damaged, please contact your dealer immediately.

SAFETY INFORMATION
This Meter complies with the standards IEC61010: in pollution degree 2, overvoltage category (CAT. III 600V, CAT IV 300V), and double insulation. CAT. Distribution level, fixed installation, with smaller transient overvoltages than CAT. IV CAT.IV: Primary supply level, overhead lines, cable systems, etc. Use the Meter only as specified in this operating manual, otherwise, the protection provided by the Meter may be impaired. In this manual, a Warning identifies conditions and actions that pose hazards to the user or may damage the Meter or the equipment under test. A Note identifies the information that the user should pay attention to.

 RULES FOR SAFE OPERATION

WARNING : To avoid possible electric shock or personal injury, and to avoid possible damage to the Meter or to the equipment under test, adhere to the following rules:

•  Before using the Meter inspect the case. Do not use the Meter if it is damaged or the case (or part of the case) is removed. Look for cracks or missing plastic. Pay attention to the insulation around the connectors.
•  Inspect the test leads for damaged insulation or exposed metal. Replace damaged test leads with identical model numbers or electrical specifications before using the Meter.
•  Do not apply more that the rated voltage, as marked on the Meter.
•  When the measurement has been completed, disconnect the connection between the test leads and the circuit under test, remove the test leads from the input terminals of the Meter and turn the Meter power off.
•  Do not carry out the measurement when the Meter’s back case and/or battery door is opened to avoid electric shock.
•  When the Meter working at an effective voltage over 30V in AC, special care should be taken.
•  Use the proper terminals and functions for your measurements.
•  Do not use or store the Meter in an environment of high temperature, humidity, explosive, inflammable, and strong magnetic field. The performance of the Meter may deteriorate after being dampened.
•  Do not use the Meter if the surface of it is wet or the user’s hands are wet.
• When using the test leads, keep your fingers behind the finger guards. Replace the battery as soon as the battery indicator appears.
• With a low battery, the Meter might produce false readings that can lead to electric shock and personal injury.
•  When opening the battery door, make sure the Meter is off.
•  When servicing the Meter, use only the same model number or identical electrical specifications replacement parts.
•  The internal circuit of the Meter shall not be altered at will to avoid damage of the Meter and any accident.
•  Soft cloth and mild detergent should be used to clean the surface of the Meter when servicing. No abrasive or solvent should be used to clean the surface of the Meter.
•  The Meter is suitable for indoor use.
•  Turn the Meter off when it is not in use and take out the battery when not used for a long time.
•  Constantly check the battery as it may leak when it has not been used for some time, and replace the battery as soon as leaking appears. A leaking battery will damage the Meter.

THE METER STRUCTURE
The Meter Back and Bottom Structure (see figure 1)

The Meter Front Structure (see figure 2)

1. Transformer Jaw: designed to pick up the AC and DC current flowing through the conductor. It could transfer current to voltage. The tested conductor must vertically go through the Jaw center.
2.  Hand Guards: to protect the user’s hand from touching the dangerous area.
3.  MR button (recall data)
4.  SEL / ▲ button (press to select phase and sum of Watts measurement)
5.  MAX MIN/button
6.  SAVE button (data store button)
7.  LCD Display
8. L2 Input Terminal (Second phase measurement)
9.  L3 Input Terminal (Third phase measurement)
10.  COM Input Terminal
11.  L1 Input Terminal (First phase measurement)
12.  USB button
13.  CLEAR button
14. RIGHT button (auto display backlight button)
15.  Σ button (Sum)
16.  HOLD button
17.  Rotary function switch
18.  NCV indicate lamp

FUNCTION
The below table indicated information about the functional button operations.

1.  Turn the rotary switch dial to a position away from the OFF position. Hearing a beep sound indicates the meter is turned on. The LCD displays all symbols first and then returns to the normal mode. If the symbol is displayed, please change the battery.
2.  After auto-shut-off, there are some parts of the circuit of the meter which still work. If no measurement is needed in a longer time, you’d better turn the rotary switch back to the OFF position.
3.  Press the backlight button when needed. Auto shut down backlight after 20 secs. Press the button again, turn the backlight off manually

DISPLAY SYMBOLS (See figure 3)

MEASUREMENT OPERATION

Preparation

•  Dial the Rotary to any active measure range
•  Replace the battery as soon as the battery indicator appears on the display.
• Non-Contact Voltage Detector

WARNING : Risk of Electrocution. Before use, always test the Voltage Detector on a known live circuit to verify proper operation.

1.  Rotate the Function switch to any measurement position.
2.  Place the detector probe tip on the conductor to be tested.
   NOTE: The conductors in electrical cord sets are often twisted. For best results, move the probe tip along a length of the cord to assure placing the tip close to the live conductor.
   NOTE : The detector is designed with high sensitivity. Static electricity or other sources of energy may randomly trip the sensor. This is a normal operation.

AC Voltage (main display) + Frequency (secondary display) Measurement (see figure 4)

The AC Voltage ranges are:100V, 400V and 750V
The frequency range is:50Hz~60Hz
To measure AC voltage + frequency, connect the Meter as follows:

1.  Insert the red, blue, and yellow test lead into the L1, L2, and L3 input terminal, and the black test lead to the COM input terminal.
2.  Dial the Rotary to VAC to select Voltage + Frequency range.
3.  Connect the red, blue, and yellow test leads (L1, L2, L3 input terminal)to the corresponding three phases loaded live wire. Black test lead (COM input terminal) to the corresponding three phases loaded neutral wire.
4. Press SEL to select the phase location, and the display shows the corresponding phase symbol. L1 means the first phase , Ø1 L2 means the second phase , Ø2 L3 means the third phase .Ø3
5. The display shows the corresponding True RMS voltage value and the frequency value of each phase.
6. Press MAX MIN, and the LCD display, it starts recording the maximum AC voltage True RMS value.
7. Press MAX MIN on the LCD displays, it starts recording the minimum AC voltage True RMS value. Press MAX MIN again to show the current AC voltage True RMS value.
8.  The display shows 0L when the input voltage is higher than 750V RMS.
   Note: When the measurement has been completed, disconnect the connection between the test leads and the circuit under test and remove test leads from the input terminals.

AC Current (main display) + AC Voltage (secondary display)Measurement (see figure 5)

The AC current ranges are: 40A, 100A, 400A and 1000A The AC Voltage ranges are: 100V, 400V and 750V To measure AC current + AC voltage, connect the Meter as follows:

1.  Dial the Rotary to AAC to select AC Current + AC Voltage range.
2.  Press the lever to open the transformer jaw.
3.  Center the conductor within the transformer jaw, then release the Meter slowly until the transformer jaw is completely closed, Make sure the conductor to be tested is placed at the center of the transformer jaw, otherwise, it will cause deviation. The Meter can only measure one conductor at a time, to measure more than one conductor at a time will cause deviation.
4.  The double display shows the AC current True RMS value and AC voltage True RMS value.
5. Press MAX MIN and the LCD displays, and it starts recording the maximum AC current True RMS value.
6. Press MAX MIN, the LCD displays, it starts recording the minimum AC current True RMS value. Press MAX MIN, again to show the present AC current True RMS value.
7. The display shows 0L when the current of the tested conductor is higher than 1000A rms.
   Note: When the measurement has been completed, disconnect the connection between the conductor under test and the jaw, and remove the conductor away from the transformer jaw of the Meter.

Active Power (main display) + Phase Angle (secondary display) Measurement

WARNING : To avoid damage to the Meter or harm to you, do not measure higher than AC voltage 750 v and AC current 1000A.To measure active power + phase angle, connect the Meter as follows:

1.  Dial the Rotary to KW to select Active power + Phase angle range.
2.  Press the lever to open the transformer jaw, and clamp them to the corresponding phase of the tested conductor. If the user needs to measure any phase of the 3 phases, then clamp them to that phase’s conductor.
3.  Connecting method (see Figures 6, 7, 8):
4.  Insert red, blue, yellow test leads to L1, L2, L3 input terminal and connect it to every live wire of the 3 phase.
5.  Insert black test leads to the COM input terminal and connect it to the neutral wire of the 3 phase. When measuring 3 phase 4 wires, connecting the Meter as figure 6.

Measuring Instruction

1. Press SEL to choose the first phase, see figure 7Ø1. The double displays show the active power kW value and the PG value of the second phase 1.
2. If necessary, press Σ to get the sum of watts as figure 8. After recording the current power measurement value of the first phase, then press SEL Ø2 to choose. The double display shows the value of active power kW and PG of the second phase 2. as in figure 9.
3. If necessary, press Σ to get the sum of watts as figure 10.
4. After recording the current power measurement value of the second phase, then press SEL Ø3 again to choose. The double display shows the value of active power KW and PG of the third phase, as in figure 11.
5. If necessary, press Σ to get the sum of watts as figure12
6. After recording the current power measurement value of the third phase, finally, press Σ and hold for 1seconds to display the 3-phase sum of active power value and apparent power value, as in figure 13.
7. Press ▲ as figure 14 to step through in sequence three phase sum of active power+three phase sum of reactive power, and three phase sum of power factor + 3 phase sum of apparent power.

Press Σ and hold for 1 second again to change back to the normal measuring mode.
In figure 6 ΣW = W1 + W2 + W3.

• When measuring 3 phase 3 wires, Hold SEL for 5 seconds and the Meter shows, press SEL again for 5 seconds to exit 3 phase 3 wires, connecting the Meter as figure 15.

1.  Insert blue, red test leads to L1, L3 input terminal.

2.  Insert the black test leads to the COM input terminal and connect it to the neutral wire of the 3 phase.

3.  Jump over to the second phase measurement.
   NOTE

   • It can only sum up the current measurement value. The maximum and minimum value cannot be summed up.
   •  Only at KW range can you carry out sum of watts measurement, other ranges cannot carry out this measurement.
   •  When testing has been completed, disconnect the connection between the test leads and the circuit under test and remove test leads from the input terminals.

Apparent Power (main display) + Reactive Power (secondary display) Measurement

• Please refer to C

Reactive Power (main display) + Apparent Power (secondary display) Measurement

• Please refer to C.

WARNING: To avoid damage to the Meter or harm to you, do you measure higher than AC voltage 750V rms and AC current 1000A rms. To test for Power factor (main display) + Phase angle (secondary display), connect the Meter as follows:

1.  Dial the Rotary to cosθ to select Power factor + Phase angle range.
2.  Press the lever to open the transformer jaw, and clamp them to the corresponding phase of tested conductor. If user needs to measure any phase of the 3 phase, then clamp them to that phase’s conductor.
3.  The connecting method of 3 phases 4 wires or 3 phases 3 wires, refer to figure 6 and 15
4.  When measuring 3 phase 4 wires: (see figure 18, 19 and 20)

The double display shows the first phase value of power factor PF and phase angle PG. Then press SEL again to choose the second phase, see figure 19.

• Press SEL to choose the second phase, see figure 19.

The double display shows the second phase value of power factor PF and phases angle PG. Then press SEL again to choose the third phase, see figure 20.

• Press SEL to choose the third phase, see figure 20.

When measuring 3 phase 3 wires

•  The first phase and third phase operating method is the same as 3 phase 4 wires.
•  Jump over the second phase measurement.

WARNING: To avoid damage to the Meter or harms to you, do you measure higher than AC voltage 750V rms and AC current 1000A rms.To test for Active Energy (main display) + Time (secondary display), connect the Meter as follows:

•  Dial Rotary to ENERGY range.

•  Press the lever to open the transformer jaw, and clamp them to the corresponding phase of the tested conductor. If user needs to mesaure any phase f  3 phase, then clamp them to that phase’s conductor.

•  The connecting method of 3 phase 4 wires and 3 phases 3 wires see figure 6 and 15

• Press SEL to choose one of the three phases, see figure 21.

• The double display shows the value of the tested object’s active energy kWh value and the measuring time of the corresponding phase.

•  The measuring reading increases along with the time increase. Press HOLD to read a particular time kWh value. Then the reading and time are locked, but still continuously accumulate measuring time.

•  After reading the data, press HOLD again to continuous measurement. kWh value continues to accumulate and the measuring time jumps to the present measuring time.

•  When the measuring time is over 24 hours or the Meter is switched to other measuring ranges, active energy measuring will stop.

• The maximum reading of active energy is 9999kWh. OL will be displayed when the reading is over than that.

•  When there is no input signal, it cannot carry out active energy measurement.

•  When testing has been completed, disconnect the connection between the testing leads and the circuit under test and remove testing leads from the input terminals.

TRUE RMS MEASUREMENT AND AVERAGE VALUE MEASUREMENT

The True RMS measurement method can measure accurately the effective value of a non-sine wave input signal. Average value measurement method can measure the mean value of one sine wave input signal, and then displays it as an RMS value When the input waveform has distortion, measuring tolerance will be included. The total tolerance depends on the total distortion. Table 1 shows the waveform coefficient and the relationship and the requested changing factor of sine wave, square wave, value and average value. The clamp Meter software designing base on the following formula:

•  KW = KVA × Cosθ
•  KVAr = KVA × Sinθ
• KVA = KW² +KVAr²

SPECIFICATIONS

Accuracy

Function                                                  Range

(a% reading + b digits)| guarantee for 1 year.
Operating temperature| 23℃±5℃
Operating humidity| 45~75%R.H

AC Voltage (True RMS)

Range| Resolution| Accuracy| Allowable Maximum Overload Protection

Voltage

| Input Impedance| Frequency Range
---|---|---|---|---|---
100V| 0.1V| ±(1.2%+5)| 750 RMS| 10M| 50Hz~200Hz
400V
750V

Frequency

AC Current (True RMS)

Range| Resolution| Accuracy| Allowable Maximum Overload Protection

Voltage

| Frequency Range
---|---|---|---|---
40A| ****

0.1A

| ****

±(2%+5)

| ****

1000A RMS

| ****

50Hz~60Hz

100A
400A
1000A| 1A

Active Power (W=V x A x COSθ)

Current / Voltage                     Voltages Range

 | 100V| 400V| 750V
Current Range| 40A| 4.00KW| 16.00KW| 30.00KW
100A| 10.00KW| 40.00KW| 75.00KW
400A| 40.00KW| 160.0KW| 300.0KW
1000A| 100.0KW| 400.0KW| 750.0KW
Accuracy| ±(3%+5)
Resolution| <1000KW: 0.01KW 100kW: 0.1KW

Apparent Power (VA = V x A)

Current / Voltage                     Voltages Range

 | 100V| 400V| 750V
Current Range| 40A| 4.00KVA| 16.00KVA| 30.00KVA
100A| 10.00KVA| 40.00KVA| 75.00KVA
400A| 40.00KVA| 160.0KVA| 300.0KVA
1000A| 100.0KVA| 400.0KVA| 750.0KVA
Accuracy| ±(3%+5)
Resolution| <1000KVA: 0.01KVA 100kW: 0.1KVA

Reactive Power (Var = V x A x SINθ)

Current / Voltage                     Voltages Range

 | 100V| 400V| 750V
Current Range| 40A| 4.00KVAr| 16.00KVAr| 30.00KVAr
100A| 10.00KVAr| 40.00KVA| 75.00KVAr
400A| 40.00KVAr| 160.0KVAr| 300.0KVAr
1000A| 100.0KVAr| 400.0KVAr| 750.0KVAr
Accuracy| ±(3%+5)
Resolution| <1000KVAr: 0.01KVAr 100kW: 0.1KVAr

Power Factor (PF = W / VA)

0.3~1

(capacitive or inductive)

| ±0.022| 0.001| The minimum measuring current 10A The minimum measuring voltage 45V
0.3~1

(capacitive or inductive)

| For reference only| Measuring current less than 10A OR

Measuring voltage less than 45V

Phase Angle (PG=acos (PF))

0°~90°

(capacitive or inductive)

| ±2°| 1°| The minimum measuring current 10A The minimum measuring voltage 45V
0°~90°

(capacitive or inductive)

| For reference only| Measuring current less than 10A OR

Measuring voltage less than 45V

Active Energy (kWh)

Special Functions
Auto Ranging|  | √
Single-phase 2-wire|  | √
Balance 3-phase 3-wire|  | √
3-phase 4-wire|  | √
True RMS AC| Voltage or Current| √
Data Logging| 99| √
Data Recall|  | √
Max/Min Mode|  | √
Data Hold|  | √
USB|  | √
Display Backlight|  | √
Full Icon Display|  | √
Sleep Mode|  | √
Low Battery Display|  | √
Input Impedance for AC Voltage Measurement| Around 10MW| √
Max. Display| 9999| √
Analogue Bar Graph|  | √

www.major-tech.com sales@major-tech.com www.majortech.com.au info@majortech.com.au

References

• Major Tech - Innovation l Quality l Excellence
• Home - Major Tech Australia

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