Major tech MT 770 User manual

MT 770
AC CLAMP METER
INSTRUCTION MANUAL
© 2004, MAJOR TECH (PTY) LTD. All rights reserved

1. Measuring Limits ........................... 1
2. Safety Warnings ............................ 2
3. Features ......................................... 4
4. Instrument Layout ......................... 5
5. Specifications ................................ 5
6. AC Current Measurement ............. 7
7. DC Voltage Measurement ............. 8
8. AC Voltage Measurement ............. 9
9. Resistance Measurement ............. 10
10. Capacitance Measurement ........... 11
11. Frequency Measurement .............. 12
12. Duty Cycle Measurement ............. 13
13. Temperature Measurement .......... 14
14. Diode Test ...................................... 15
15. Continuity Testing ......................... 16
16. Other Functions ............................ 17
17. Battery Replacement .................... 18
18. Standard Accessories ................... 18
MEASURING LIMITS
AC Amperes : 0.1A to 1000A
DC Voltage : 0.1mV to 600V
AC Voltage : 0.1mV to 600V
Resistance : 0.1Ω to 40MΩ
Capacitance : 0.01 nF to 100µF
Frequency : 0.001 Hz to 10MHz
Duty Cycle : 0.5% to 99.0%
Temperature : -20 ºC to 1000 ºC
- 4 ºF to 1832 ºF
1
CONTENTS

2
1. SAFETY INFORMATION
This manual contains information that must be
followed for operating the meter safely and
maintaining the meter in a safe operating
condition. If the meter is not used in a manner
specified in this manual, the protection provided
by the meter may be impaired
The Model MT770 has been designed and
complies with IEC 61010-1 and EN 61010-1
Safety Requirements for Electronic Measuring
Apparatus.
WARNING
! Read through the operating instructions
throughly and understand the instructions
before operating the meter.
! Keep the manual at hand so as to enable
quick reference when necessary
! Ensure that the use of the meter is in its
intended applications and follow
measurement procedures described in this
manual.
! Follow all safety and operating instructions to
ensure maximum personal safety during the
use and operation of the meter.
! Failure to follow the above instructions may
cause injury, instrument damage and/or
damage to equipment under test.
!The symbol indicated on the meter means that
the user must refer to related parts in the
manual for safe operation of the meter. Be
sure to carefully read the instructions following
each symbol in this manual.
DANGER is reserved for conditions and
actions that are likely to cause serious or fatal
injury
WARNING is reserved for conditions and
actions that are likely to cause serious or fatal
injury
CAUTION is reserved for conditions and
actions that are likely to cause minor injury or
!
!
!
!

DANGER
! Never use the meter to measure voltages on a
circuit above the maximum allowable input
value on any function.
! Do not exceed the maximum allowable input
of any measurement range.
! Never touch exposed wiring, connections or
any live circuit when attempting to take
measurements.
! Do not attempt to make measurements in
flammable gaseous areas, fumes, vapor or
dust. The use of the instrument in these areas
may cause sparking , which can lead to an
explosion.
! Do not attempt to use the instrument if its
surface or your hand is wet
! Never open the battery compartment cover
when making measurements.
WARNING
! Always inspect the meter and test leads for
any signs of damage or abnormality before
use. If the meter or its accessories have any
structural defects such as broken test leads,
cracked cases, exposed metal parts or the
display is not reading, do not attempt to make
measurements.
! Do not turn the function switch whilst test
leads are connected to the meter.
! Do not install substitute parts or make
modifications to the meter. Return the meter
to your distributor for repair or re-calibration.
! Ensure the meter is switch off before opening
the battery cover when replacing the battery.
! Never replace a battery if the surface of the
meter is wet or moist.
3
!!
!

CAUTION
! Before making measurements ensure that the
function selector switch is set on the
appropriate range position.
! Always make sure that the plug of each test
lead is inserted fully into the appropriate
terminal of the meter.
! Ensure that the function selector switch is set
to the “OFF” position after use. When the
meter will not be in use for a long period of
time, place it in storage after removing the
battery.
! Do not expose the meter to direct sunlight,
extreme temperatures or moisture.
! Do not use abrasives or solvents on the meter.
To clean it use a damp cloth and mild
detergent only.
Qualified and trained service technicians should
only perform calibration and repair of the meter.
2. FEATURES
! Large 4000 count LCD display with bright
white LED backlight.
! Wide measuring range from 0.01A AC up to
1000A AC
! Measures AC and DC Voltage up to 600 volts
! Measures resistance from 0.01Ω up to 40MΩ.
! Capacitance measurements up to 100µF
! Temperature measurement from -20ºC to
+1000ºC and -4ºF to +1832ºF.
! Designed to the international safety standard
IEC61010 CAT lll 600V / CAT ll 1000V,
Pollution degree 2.
! Auto Power Off after approximately 30
minutes to conserve battery life.
! Continuity Buzzer and Diode Test
! Frequency measurement up to 10MHz, with
Duty Cycle testing
! Data Hold switch used to freeze reading on
display
4
!!

3. INSTRUMENT LAYOUT
Transformer
Jaws
Function
Switch
Jaw Trigger
Data Hold
& Backlight
Switch
Mode Switch
Display
COM
Terminal
Volt, Resistance,
Frequency,
Temperature
Terminal
Frequency,
Duty Cycle
Switch
Range Selector
Switch for Volts
and Resistance
Clamp Size
Diode Test
Continuity Check
Low Battery Indication
Overrange Indication
Measurements Rate
Input Impedance
Display
AC Current
AC Voltage Bandwidth
Operating Temperature
Storage Temperature
Relative Humidity
Over Voltage
Battery
Auto Power Off
Dimensions
Weight
30mm Opening Approx
Test Current of 0.3mA typical;
Open circuit voltage 1.5V DC
Threshold <100Ω; Test current <1mA
“ “ is displayed
“OL” is displayed
2 per second, nominal
7.8MΩ (VDC and VAC)
4000 count LCD
50/60Hz (AAC)
50/60Hz (VAC)
-10ºC to 50ºC (-14ºF to 122ºF)
-30ºC to 60ºC (-14ºF to 140ºF)
Up to 85%
Category lll 600V
One PP3 “9V” Battery
Approx 30 minutes
229 x 80 x 49mm
303g
4. SPECIFICATIONS
+
5

4. SPECIFICATIONS
Range
AC Current
Measuring Range Resolution
40A
400A
1000A
0 ~ 40.00A
0 ~ 400.0A
0 ~ 1000A
0.01 A
0.1 A
1 A
Accuracy (% of Reading)
± (2.5% + 10 digits)
± (2.5% + 5 digits)
± (3.0% + 5 digits)
Range
DC Voltage
Measuring Range Resolution
400mV
4V
40V
400V
600V
0 ~ 400.0mV
0 ~ 4.000V
0 ~ 40.00V
0 ~ 400.0V
0 ~ 600V
0.1 mV
0.001 V
0.01 V
0.1 V
1 V
Accuracy (% of Reading)
± (0.8% + 3 digits)
± (1.5% + 3 digits)
± (2.0% + 3 digits)
Range
AC Voltage
Measuring Range Resolution
400mV
4V
40V
400V
600V
0 ~ 400.0mV
0 ~ 4.000V
0 ~ 40.00V
0 ~ 400.0V
0 ~ 600V
0.1 mV
0.001 V
0.01 V
0.1 V
1 V
Accuracy (% of Reading)
± (0.8% + 10 digits)
± (1.8% + 5 digits)
± (2.5% + 5 digits)
Range
Resistance
Measuring Range Resolution
400Ω
4kΩ
40kΩ
400kΩ
4MΩ
40MΩ
0 ~ 400.0Ω
0 ~ 4.000kΩ
0 ~ 40.00kΩ
0 ~ 400.0kΩ
0 ~ 4.000MΩ
0 ~ 40.00MΩ
0.1 Ω
1Ω
10 Ω
100 Ω
1 kΩ
10 kΩ
Accuracy (% of Reading)
± (1.0% + 4 digits)
± (1.5% + 2 digits)
± (2.5% + 3 digits)
± (3.5% + 5 digits)
Note: No Autoranging on 400mV AC Range
Range
Capacitance
Measuring Range Resolution
40nF
400nF
4µF
40µF
100µF
0 ~ 40.00nF
0 ~ 400.0nF
0 ~ 4.000µF
0 ~ 40.00µF
0 ~ 100.0µF
0.01 nF
0.01 nF
0.001 µF
0.01 µF
0.1 µF
Accuracy (% of Reading)
± (5.0% + 20 digits)
± (3.0% + 5 digits)
± (3.5% + 5 digits)
± (5.0% + 5 digits)
Range
Frequency
Measuring Range Resolution
5Hz
50Hz
500Hz
5kHz
50kHz
500kHz
5MHz
10MHz
0 ~ 5.000Hz
0 ~ 50.00Hz
0 ~ 500.0Hz
0 ~ 5.000kHz
0 ~ 50.00kHz
0 ~ 500.0kHz
0 ~ 5.000MHz
0 ~ 10.00MHz
0.001 Hz
0.01 Hz
0.1 Hz
1 Hz
10Hz
100 Hz
1 kHz
10 kHz
Accuracy (% of Reading)
± (1.5% + 5 digits)
± (1.2% + 2 digits)
Sensitivity: 10Vrms min
± (1.2% + 10 digits)
Range
Duty Cycle
Measuring Range Resolution
%0.5% ~ 99.0%
Pulse width:
100µs - 100ms
0.1 %
Accuracy (% of Reading)
± (1.2% + 2 digits)
Range
Temperature
Measuring Range Resolution
ºC
ºF
-20.0ºC ~ 400.0ºC
400ºC ~ 1000ºC
-4.0ºF ~ 400.0ºF
400ºF ~ 1832ºF
0.1 ºC
1 ºC
0.01 ºF
1 ºF
Accuracy (% of Reading)
± (3.0% + 5ºC)
± (3.0% + 7ºF)
6

5. AC CURRENT MEASUREMENT
WARNING: Ensure that the test leads are
disconnected from the meter before making
current measurements.
1. Set the function switch to or or
range position, and make sure that the
current under test does not exceed the upper
limit of the measuring range you have
selected.
2. Press the trigger to open up the transformer
jaws and clamp around the single conductor
under test.
3. Read the display.
Note: • During current measurements keep the
transformer jaws fully closed, otherwise
this will affect the accuracy of the
measurement.
• When large currents the transformer
jaws may buzz. This is not a fault and
does not affect the accuracy of the
reading.
40A
~
400A
~
1000A
~
Correct Current
Measurement
Incorrect Current
Measurement
7
!!

+
-
6. DC VOLTAGE MEASUREMENT
1. Set the function switch to range
position. The meter automatically defaults to
DC Volts.
2. Insert the red test lead into the “V Ω ºC ºF HZ”
input terminal and the black lead to the “COM”
terminal.
3. Connect the other end of the test leads to the
circuit under test.
4. Read the display. If a “-” sign is displayed, the
red lead is the negative potential.
Note: • The meter is set to default to “Auto
Range” mode.
• Pressing the button transforms
the meter into a ‘Manual Range” mode.
This means that the user will have to
depress this button to select the correct
range for the voltage being measured.
• In order to return back to the “Auto
Range” mode, hold down the
button for 3 seconds.
V
__
~
RANGE
RANGE
Battery
8

AC Supply
7. AC VOLTAGE MEASUREMENT
1. Set the function switch to range
position.
2. Press the ” button to select the AC Volt
range. The meter automatically defaults to DC
Volts.
3. Insert the red test lead into the “V Ω ºC ºF HZ”
input terminal and the black lead to the “COM”
terminal.
4. Connect the other end of the test leads to the
circuit under test. Take the reading on the
display.
Note: • The meter is set to default to “Auto
Range” mode.
• Pressing the button transforms
the meter into a ‘Manual Range” mode.
This means that the user will have to
depress this button to select the correct
range for the voltage being measured.
• In order to return back to the “Auto
Range” mode, hold down the
button for 3 seconds.
• To test Frequency on AC Voltage simple
press the button.
MODE
RANGE
RANGE
V
__
~
9
%
Hz
•

!!
8. RESISTANCE MEASUREMENT
1. Set the function switch to range
position. The meter automatically defaults to
resistance range.
2. Insert the red test lead into the “V Ω ºC ºF HZ”
input terminal and the black lead to the “COM”
terminal.
3. Connect the other end of the test leads to the
circuit or component under test. Take the
reading on the display.
Note: • The meter is set to default to “Auto
Range” mode.
• Pressing the button transforms
the meter into a ‘Manual Range” mode.
This means that the user will have to
depress this button to select the correct
range for the resistance being
measured.
• In order to return back to the “Auto
Range” mode, hold down the
button for 3 seconds.
• WARNING before attempting to
make a resistance measurement, ensure
there is no voltage present on the circuit
under test.
Ω
RANGE
RANGE
Resistor
10

11
9. CAPACITANCE MEASUREMENT
1. Set the function switch to range
position.
2. Press the button to select the
Capacitance range. The meter automatically
defaults to Resistance.
3. Insert the red test lead into the “V Ω ºC ºF HZ”
input terminal and the black lead to the “COM”
terminal.
4. Connect the other end of the test leads to the
circuit or component under test. Take the
reading on the display.
Note: • In Capacitance range the meter is Auto
Ranging only.
• CAUTION to avoid damage to the
meter or the equipment under test,
remove all power from the circuit and
discharge all capacitors before
measuring capacitance.
• Large value capacitors should be
discharged through an appropriate
resistance load. Use the DC Voltage
function to confirm that the capacitor is
discharged.
MODE
Ω
Capacitor
!!

10. FREQUENCY MEASUREMENT
1. Set the function switch to range position.
The meter automatically defaults to Frequency
range.
2. Insert the red test lead into the “V Ω ºC ºF HZ”
input terminal and the black lead to the “COM”
terminal.
3. Connect the other end of the test leads to the
circuit or component under test. Take the
reading on the display.
Note: • In the Frequency range the meter is Auto
Ranging only.
%
Hz
•
Measuring Frequency
on AC Supply
Hz
12

11. DUTY CYCLE MEASUREMENT
Duty Cycle (or Duty Factor) is the percentage of time a
signal is above or below a trigger level during one cycle.
The Duty Cycle mode is optimized for measuring the On
or OFF time of logic and switching circuits. Systems
such as electronic fuel injection systems and switching
power supplies are controlled by pulses of varying
width, which can be checked by measuring the Duty
Cycle.
1. Set the function switch to range position.
The meter automatically defaults to Frequency
range.
2. Press the button to select the Duty
Cycle range. The meter automatically defaults
to Resistance.
3. Insert the red test lead into the “V Ω ºC ºF HZ”
input terminal and the black lead to the “COM”
terminal.
4. Connect the other end of the test leads to the
circuit or component under test. Take the
reading on the display.
Note: • In the Duty Cycle range the meter is Auto
Ranging only.
%
Hz
•
%
Hz
•
ab
Duty Cycle : % duty = x 100
a
b
__
13

12. TEMPERATURE MEASUREMENT
1. Set the function switch to range position.
The meter automatically defaults to ºC range.
2. Insert the MT802 white temperature adaptor
into the “V Ω ºC ºF HZ” input terminal and the
“COM” terminal. Ensure that the “-” marking on
the adaptor is inserted into the “COM” terminal
and the “+” marking on the adaptor is inserted
into the “V Ω ºC ºF HZ” input terminal.
3. Connect any K-Type probe into the Mt802
adaptor and measure the temperature of the
apparatus or area required.
4. Read the temperature directly on the display.
5. To change the measuring unit from ºC to ºF,
Press the button to select the ºF unit.
Note: • The meter is set to default to “Auto
Range” mode.
• Pressing the button transforms
the meter into a ‘Manual Range” mode.
This means that the user will have to
depress this button to select the correct
range for the temperature being
measured.
• In order to return back to the “Auto
Range” mode, hold down the
button for 3 seconds.
RANGE
RANGE
ºF
•
ºC
MODE
Ambient Temperature
K-Type Adaptor
K-Type
Wire Probe
14

13. DIODE TEST
1. Set the function switch to range
position.
2. Press the button to select the Diode
Test range. The meter automatically defaults to
Resistance.
3. Insert the red test lead into the “V Ω ºC ºF HZ”
input terminal and the black lead to the “COM”
terminal.
4. Connect the other end of the test leads to the
component under test. Read the display.
Note:• Use the diode test to check diodes,
Transistors, silicon controlled rectifiers
(SCR’s) and other semiconductor devices.
• The test sends a current through a
semiconductor junction, then measures
the junction’s voltage drop.
• Normal forward voltage drop (forward bias)
for a good silicon diode is between 0.4V to
0.9V. A reading higher than that indicates
a leaky (defective) diode. A zero reading
indicates a shorted diode.
• Reverse the test leads connection (reverse
bias) across the diode. The display shows
“OL” if the diode is good. Any other
readings indicate the diode is shorted or
resistive (defective).
MODE
Ω
Diode
15

14. CONTINUITY TESTING
1. Set the function switch to range
position.
2. Press the button to select the Continuity
Test range. The meter automatically defaults to
Resistance.
3. Insert the red test lead into the “V Ω ºC ºF HZ”
input terminal and the black lead to the “COM”
terminal.
4. Short the tip of the test leads and make sure the
display reads “0” and the buzzer beeps.
5. Connect the tip of the test leads to the circuit or
component under test. The display reads the
resistance and the buzzer beeps when the
reading is not more than about 100Ω.
Note: • Using resistance and continuity function
in a live circuit will produce false results
and may damage the instrument.
• In many cases the suspicious
components must be disconnected from
the circuit under test to obtain accurate
results
• WARNING before attempting to
make a test, ensure there is no voltage
present on the circuit. .
MODE
Ω
Buzzer Sounds
16
!!

15. DATA HOLD
This is a function used to freeze the reading on
the display, ideal for later viewing.
1. Press the button once. When the Hold is
activated, the meter beeps, freezes the
reading, and displays the “HOLD” indicator on
the LCD.
2. To deactivate the “HOLD” function, press
button once, the meter will beep and the meter
will start reading new measurements.
16. LCD BACKLIGHT
The backlight is ideally used in dark or dimly lit
areas.
1. Press the button for 3 seconds, and the
bright white light will come on together with the
Data Hold.
2. To deactivate the “HOLD” function, press
button once, the meter will beep and the meter
will start reading new measurements with the
light on.
3. To turn off the backlight press the button
for 3 seconds.
Note: • The use of the backlight will reduce the
battery life considerably.
17. AUTO POWER OFF
This feature automatically turns off the meter after
approximately 30 minutes from the last
measurement taken. To turn the on the meter,
press any button or move the rotary switch to any
position. Ensure te test leads are disconnected
from any circuit to avoid injury or meter damage..
HOLD
HOLD
HOLD
HOLD
17

18. BATTERY REPLACEMENT
When the “ “ sign appears on the LCD, this
indicates the battery should be replaced. Use the
following procedure to replace the standard 9V
battery (IEC 6F 22) battery.
1. Disconnect the test leads from any live source
and remove the leads from the input terminals.
2. Rotate the function switch to the
position.
3. The battery cover is secured to the bottom of
the case by a screw. Using a screwdriver
remove the screw from the battery cover and
remove the battery cover from the meter.
4. Remove the old battery and replace it with a
new IEC 6F 22 9V battery.
5. Replace the battery cover and reinstall the
screw.
19. STANDARD ACCESSORIES
+
OFF
HDT 3914
Crocodile Clip
CAT lll 600V, CAT ll 1000V
10A Ratings
HDT 1282
ComfiGrip™ Test Leads
CAT lV 600V, CAT lll 1000V
10A Rating MT 660
K-Type Thermocouple
MT 802
4mm to K-type
Adaptor
Battery Cover
18

© 2004, MAJOR TECH (PTY) LTD.
All rights reserved E&OE
MAJOR TECH
(PTY) LTD
T9 Industrial Village, Sam Green Road,
Tunney Ext. 9, Elandsfontein,
South Africa
P.O. Box 888, Isando 1600,
South Africa
Telephone: [phone]
National Contact Number: 08 61 62 5678
Sales Facsimile: [phone]
Admin Facsimile: [phone]
E-mail: [email protected]
www.major-tech.com