MAJOR TECH MT790 Three Phase Power Clamp Meter Instruction Manual

Instruction Manual for MAJOR TECH models including: MT790, Three Phase Power Clamp Meter, Power Clamp Meter, Clamp Meter, MT790, Meter

MT790 MANUAL 2021

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Clamp Meter - Major Tech - MT790

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Clamp-Meter-Major-Tech-MT790

INSTRUCTION MANUAL MT790
THREE PHASE POWER CLAMP METER

Contents

Page no

1. Overview..........................................................................................4

2. Unpacking Inspection ........................................................................4

3. Safety Information ............................................................................5

4. Rules for Safe Operation ....................................................................5

5. The Meter Structure ..........................................................................6

5.1. The Meter Back and Bottom Structure ........................................6

5.2. The Meter Front Structure .........................................................7

6. Function...........................................................................................8

7. Display Symbols ...............................................................................9

8. Measurement Operation ..................................................................10

8.1. Preparation ...........................................................................10

8.2. AC Voltage (Main Display) + Frequency (Secondary Display) ........11

8.3. AC Current (Main Display) + AC Voltage (Secondary Display) ........12

8.4. Active Power (Main Display) + Phase Angle (Secondary Display) Measurement .........................................................................13

8.5. Reactive Power (Main Display)+ Reactive Power (Secondary Display) Measurement ............................................................18

8.6. Apparent Power (Main Display) + Phase Angle (Secondary Display) Measurement ............................................................18

8.7. Power Factor (Main Display) + Phase Angle (Secondary Display) Measurement .........................................................................18

8.8. Active Energy (Main Display) + Time (Secondary Display) Measurement .........................................................................20

9. True RMS and Average Value Measurement .......................................21

10.Specifications .................................................................................22

10.1. Accuracy ............................................................................22

10.2. AC Voltage (True RMS) ..........................................................22

10.3. Frequency ...........................................................................22

10.4. AC Current (True RMS) .........................................................22 10.5. Active Power ( W=V x A x COS) ..........................................22

10.6. Apparent Power (VA = V x A) .................................................23 10.7. Reactive Power (Var = V x A x SIN ) ....................................23

10.8. Power Factor (PF = W / VA) ..................................................23

10.9. Phase Angle (PG=acos (PF)) ................................................23

10.10. Active Energy (kWh) ...........................................................24

1. 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 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.

2. 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:

Item

Description

English Operating Manual

Red Test Lead

Red/Blue Test Lead

Red/Yellow Test Lead

Black Test Lead

Red Alligator Clip

Yellow Alligator Clip

Black Alligator Clip

USB Interface Cable

Software

Carry Case

9V Battery

Qty
1 piece 3 piece 1 piece 1 piece 1 piece 1 piece 1 piece 1 piece 1 piece 1 piece 1 piece 1 piece 1 piece

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

3. 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. III: 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 user should pay attention to.

4. 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 number or electrical

specifications before using the Meter.

· Do not apply more that the rated voltage, as marked on the Meter.

· When 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 function 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 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 and 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 using for a long time. · Constantly check the battery as it may leak when it has not been used for some time, replace the battery as soon as leaking appears. A leaking battery will damage the Meter. 5. THE METER STRUCTURE 5.1. The Meter Back and Bottom Structure (see figure 1)
1 - Infrared slot 2 - USB Interface Cable
Figure 1 6

5.2. The Meter Front Structure (see figure 2)

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 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 - MAXMIN / 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 - LIGHT button (auto display

backlight button)

15 - button (Sum)

16 - HOLD button

17 - Rotary function switch

18 - NCV indicate lamp

6. FUNCTION
Below table indicated for information about the functional button operations.

Button Operation Performed

Press HOLD to enter the Hold mode in any mode, H appears

HOLD

and the Meter beeps. Press HOLD again to exit the Hold mode to return to
measurement mode, the Meter beeps and, H disappears.

Press the backlight button when needed. The backlight will

auto off after 20 seconds. Press the button again to turn the

backlight off manually.

At Active power (main display) + Phase angle (secondary

display) mode, press once button to sum up the current

phase of 3 phase measurement results. Then carry out second

phase power measurement.

Press and hold for over 1 second to sum up the phase

power measurement result which had been selected.

If you didn`t select any phase of 3 phase, is invaild.

Press once to store single reading, and the Meter beeps. The

SAVE

index number shown on the left secondary display will keep on increasing. The maximum number of data store is 99,

when it has achieved 99, the Meter shows FUL .

Press SEL button to step through first phase, second phase,

SEL third phase and the sum of watts.

Press SEL and hold for over 2 second to enter 3P3W mode.

Press to start recording maximum & minimum, this is only

MAXMIN valid in voltage, current, active power and apparent power

ranges only.

At active energy range, press CLEAR and hold for over 1

CLEAR

second to reset time to zero, then restart the timing. At all other ranges, press CLEAR and hold for over 1 second

to clear stored readings.

Press once to enter Memory Record mode,MR appears and
the Meter beeps.

If the Meter steps through the sum of power press /

button to switch display of active power (main display) , sum

/ of reactive power (secondary display) , sum of power factor (main display) and sum of apparent power.

In the MR mode, press / to select recoded data.

USB Measurement data will be sent to the PC

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 firstly and then return to the normal mode. If the symbol is displayed, please changed 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
7. DISPLAY SYMBOLS (See figure 3)
Figure 3
9

Button Operation Performed

USB Data Output is in progress

Ø1 First phase symbol

Ø2 Second phase symbol

Ø3 Third phase symbol

Unit for hour mm

mm Unit for minute

HZ Hz: Hertz.The unit of frequency.

PG PG: The unit of phase angle

KVAr KVAr. The unit of reactive power

Watt: Sum of Watt

The battery is low. Warning: To avoid false readings,

which could lead to possible electric shock or personal injury, replace the battery as soon as the battery

indicator appears.

Unit for second

MAX/MIN Maximum and Minimum reading

Analogue Bar Graph

Overloading

Bar graph 0

100

CLEAR Indicator for clear the stored reading

Negative symbol

High voltage symbol

AC Indicator for AC voltage or current MR Indicator for recall the stored reading

Hz Frequency symbol

MEM Indicator for data store

FUL Indicator for data stored is full

Data hold is active

8. MEASUREMENT OPERATION 8.1. Preparation

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

appears on the

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 normal operation.
8.2. AC Voltage (main display) + Frequency (secondary display) Measurement (see figure 4)

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, yellow test lead into the L1, L2, L3 input terminal,

and black test lead to the COM input terminal.

2. Dial the Rotary to VAC to select Voltage + Frequency range.

3. Connect the red, blue, 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. 11

4. Press SEL to select phase location, 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 frequency value of each phase.
6. Press MAXMIN, the LCD displays MAX , it starts recording the
maximum AC voltage True RMS value.
7. Press MAXMIN the LCD displays MIN , it starts recording the
minimum AC voltage True RMS value. Press MAXMIN 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. 8.3. AC Current (main display) + AC Voltage (secondary display)
Measurement (see figure 5)
Figure 5
The AC current ranges are: 40A, 100A, 400A and 1000A The AC Voltage ranges are: 100V, 400V and 750V
12

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 MAXMIN, the LCD displays MAX , it starts recording the
maximum AC current True RMS value.
6. Press MAXMIN, the LCD displays MIN , it starts recording the
minimum AC current True RMS value. Press MAXMIN, 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.
8.4. Active Power (main display) + Phase Angle (secondary display) Measurement
WARNING: To avoid damages to the Meter or harms 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 tested conductor. If user needs to mesaure any phase of the 3 phase, then clamp them to that phase's conductor. 3. Connecting method (see figure 6, 7, 8): 4. Insert red, blue, yellow test leads to L1, L2, L3 input terminal and connecting it to every live wire of the 3 phase. 5. Insert black test leads to 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.
13

Red
Figure 6
Measuring Instruction
1. Press SEL to choose first phase Ø1, see figure 7. The double displays
show the active power kW value and the PG value of the second phase 1.
Figure 7
14

If necessary, press to get the sum of watts as figure 8.
Figure 8
2. After recording the current power measurement value of the first phase,
then press SEL to chooseØ2 . The double display shows the value of
active power kW and PG of the second phase 2. as in figure 9.
Figure 9
If necessary, press to get the sum of watts as figure 10.
Figure 10 15

3. After recording the current power meaursuremnt value of the second
phase, then press SEL again to chooseØ3 . The double display shows
the value of active power KW and PG of the third phase, as in figure 11.
Figure 11
If necessary, press to get the sum of watts as figure12
Figure 12
4. After recording the current power measurement value of the third phase, finally press and hold for 1seconds to display the 3 phase sum of active power value and apparent power value, as in figure 13.
Figure 13 16

Press as figure 14 to step through in sequence threephase sum of active power+three phase sum of reactive power, and three phase sum of power factor + 3 phase sum of apparent power.

Figure 14
Press and hold for 1 second again to change back to the normal measuring mode. In figure 6 W = W1 + W2 + W3. · When measuring 3 phase 3 wires, Hold SEL for 5 seconds and the
Meter shows 3Ø3W , press SEL again for 5 seconds to exit 3 phase 3 wires, connecting the Meter as figure 15.

Blue

Red Yellow

Black Red

Figure 15

1. Insert blue, red test leads to L1, L3 input terminal. 2. Insert black test leads to COM input terminal and connect it to the
neutral wire of the 3 phase. 3. Jump over to the second phase measurement. 4. The first and the third phase measuring method is same as 3 phase 4
wires. In figure 15 W = W2 + W3. 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.
8.5. Apparent Power (main display) + Reactive Power (secondary display) Measurement
· Please refer to C
8.6. Reactive Power (main display) + Apparent Power (secondary display) Measurement
· Please refer to C.
8.7. Power Factor (main display) + Phase Angle (secondary display) Measurement
WARNING: To avoid damages 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 cos 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) · Press SEL to choose the first phase , see figure 18.
18

Figure 18
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.
Figure 19
The double display shows the second phase value of power factor PF and phase angle PG. Then press SEL again to choose the third phase, see figure 20. · Press SEL to choose the third phase, see figure 20.
Figure 20 19

5. When measuring 3 phase 3 wires: · The first phase and third phase operating method is same as 3 phase 4
wires. · Jump over the second phase measurement. 6. MAXMIN button are not valid when measuring power factor.
8.8. Active Energy (main display) + Time (secondary display) Measurement
WARNING: To avoid damages 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: 1. Dial Rotary to ENERGY range. 2. Press the lever to open the transformer jaw, and clamp them to the
corresponding phase of tested conductor. If user needs to mesaure any phase of the 3 phase, then clamp them to that phase's conductor. 3. The connecting method of 3 phase 4 wires and 3 phases 3 wires, see figure 6 and 15 4. Press SEL to choose one of the three phases, see figure 21.
Figure 21
· The double display shows the value of tested object's active energy kWh value and the measuring time of the corresponding phase.
· The measuring reading increases along with the time increasing. Press HOLD to read a particular time kWh value. Then the reading and time are locked, but still continuous accumulate measuring time.
· After reading the data, press HOLD again to continuos measurement. kWh value continuos 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.
20

· The maximum reading of active energy is 9999kWh. OL will be displayed when the reading is over than that.
5. MAXMIN are not valid when measuring active energy. 6. Press CLEAR and hold for 1 seconds to reset the time and energy. Note · 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. 9. TRUE RMS MEASUREMENT AND AVERAGE VALUE MEASUREMENT The True RMS measurement method can measure accurately the effective value of 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 RMS value When the input waveform has distortion, measuring tolerance will be included. The total tolerance depends on the total distortion. Below 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 × Cos · KVAr = KVA × Sin · KVA = KW² +KVAr²
21

10. SPECIFICATIONS 10.1. Accuracy
Function
(a% reading + b digits) Operating temperature Operating humidity

Range
guarantee for 1 year. 23±5 45~75%R.H

10.2. AC Voltage (True RMS)

Range Resolution Accuracy

Allowable Maximum Input

Frequency

Overload Protection Impedance Range

Voltage

100V 0.1V

±(1.2%+5) 750 RMS

10M

50Hz~200Hz

400V

750V

10.3. Frequency Range 50Hz~200Hz

Resolution 1Hz

Accuracy ±(0.5%+5)

10.4. AC Current (True RMS)

Range
40A 100A 400A 1000A

Resolution Accuracy Allowable Maximum Overload Protection Voltage

0.1A

±(2%+5) 1000A RMS

Frequency Range 50Hz~60Hz

10.5. Active Power (W=V x A x COS)

Current / Voltage

Voltages Range

Current 40A

Range

100A

400A

1000A

Accuracy

Resolution

100V

400V

750V

4.00KW

16.00KW

30.00KW

10.00KW

40.00KW

75.00KW

40.00KW

160.0KW

300.0KW

100.0KW

400.0KW

750.0KW

±(3%+5)

<1000KW: 0.01KW 100kW: 0.1KW

10.6. Apparent Power (VA = V x A)

Current / Voltage

Voltages Range

Current 40A

Range

100A

400A

1000A

Accuracy

Resolution

100V

400V

750V

4.00KVA

16.00KVA

30.00KVA

10.00KVA

40.00KVA

75.00KVA

40.00KVA

160.0KVA

300.0KVA

100.0KVA

400.0KVA

750.0KVA

±(3%+5)

<1000KVA: 0.01KVA 100kW: 0.1KVA

10.7. Reactive Power (Var = V x A x SIN)

Current / Voltage

Voltages Range

Current 40A

Range

100A

400A

1000A

Accuracy

Resolution

100V

400V

750V

4.00KVAr

16.00KVAr

30.00KVAr

10.00KVAr

40.00KVA

75.00KVAr

40.00KVAr

160.0KVAr

300.0KVAr

100.0KVAr

400.0KVAr

750.0KVAr

±(3%+5)

<1000KVAr: 0.01KVAr 100kW: 0.1KVAr

10.8. Power Factor (PF = W / VA)

Range

Accuracy Resolution Measuring Condition

0.3~1

±0.022

(capacitive or

inductive)

0.001 The minimum measuring current 10A The minimum measuring voltage 45V

0.3~1

For reference only Measuring current less than 10A OR

(capacitive or

Measuring voltage less than 45V

inductive)

10.9. Phase Angle (PG=acos (PF))

Range

Accuracy Resolution Measuring Condition

0°~90°

±2°

(capacitive or

inductive)

1°

The minimum measuring current 10A

The minimum measuring voltage 45V

0°~90°

For reference only Measuring current less than 10A OR

(capacitive or

Measuring voltage less than 45V

inductive)

10.10. Active Energy (kWh)

Range

Resolution

Accuracy

1~9999kWh

±(3%+2)

0.001kWh

Remarks: · Allowable maximum overload protection voltage: 750V RMS · Allowable maximum overload protection current: 1000A RMS

Basic Functions

Range

Best Accuracy

AC Voltage AC Current Active Power Apparent Power Reactive Power Power Factor Phase Angle Frequency Active Energy Temperature Special Functions Auto Ranging Single-phase 2-wire Balance 3-phase 3-wire 3-phase 4-wire True RMS AC Data Logging Data Recall Max/Min Mode Data Hold USB Display Backlight Full Icon Display Sleep Mode Low Battery Display Input Impedance for AC Voltage Measurement Max. Display Analogue Bar Graph

100V/400V/750V

±(1.2%+5digits)

40A/100A/400A/1000A

±(2%+5 digits)

0.01kW-750kW

±(3%+5 digits)

0.01kVA-750kVA

±(3%+5 digits)

0.01kVAr-750kVAr

±(4%+5 digits)

0.3~1 (Capacitive or Inductive) ±(0.02+2 digits)

0° ~90°

±2°

50Hz-200Hz

0.001~9999 kWh

±(3%+2 digits)

-50°C~1300°C / -58°F~2372°F

Voltage or Current

Around 10MW

9999

MAJOR TECH (PTY) LTD

South Africa

Australia

www.major-tech.com

www.majortech.com.au

sales@major-tech.com

info@majortech.com.au

References

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