Amprobe IR-750 Infrared-Thermometer - Manual (Page 14)

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3. See Table of Surface Emissivity for use in measuring shiny or polished metal surfaces (stainless steel,
aluminum, etc.).
4. Steam, dust, smoke, etc., can prevent accurate measurement by obstructing the instrument’s optics.
TYPICAL MEASUREMENTS
This section describes a variety of measurements often performed by technicians.
Reminder:
• User could select to turn on or off the backlight and laser whenever you are making readings with the
thermometer.
• Relatively high emissivity normally means emissivity setting of about 0.95.
• Relatively low emissivity normally means emissivity setting of about 0.30.
• When user cannot identify the emissivity of the object to be measured, user could cover the surface to be
measured (temperature >150°C) with black electric tape (emissivity of about 0.95). Allow time for the tape
to reach the same temperature as the object to be measured. Measure and record the temperature of the
tape.
Aim the thermometer to the object to be measured, adjust the emissivity setting to make it as the same temperature
as the tape. At this time, the thermometer emissivity setting is close to the emissivity of the object to be measured,
measurement can be taken.
Testing Contactors (Starters)
1. Press SET to select emissivity. Press / to select relatively low emissivity for bright contacts, or 0.7 mid
level for darkened contacts.
2. Press YELLOW button to select MAX.
3. Measure line and load side of one pole without releasing trigger.
4. A temperature difference between the line and load sides of a pole indicate increased resistance of one
point and a contactor may be failing.
Testing Enclosed Relays
1. Press SET and then press / to set emissivity to relatively low for un-insulated connectors or relatively
high for plastic encased relays or for Bakelite enclosed relays or insulated connectors.
2. Press YELLOW button to select MAX.
3. Start to scan.
4. Measure the relay casing, looking for hot spots.
5. Measure electrical connections on relay terminals looking for hot spots.