ED&D LT-952 User Manual Download Page 7

 

PRODUCT SAFETY SOLUTIONS

 

 

© 2012 Educated Design & Development, Inc. All rights reserved. Rev B: February, 2012 

                             

          

Page 6 of 19 

PRODUCT COMPONENTS: (Continued)  

A.  NEUTRAL SWITCH: Controls the connection of the incoming neutral line to the product under test.  

This switch allows the neutral to be disconnected as called for in some Standards.  With 240 Volt 
operations, this switch disconnects one side of the 240 Volt line (Line 2). 

 

B.  LINE SWITCH: Controls the connection of the incoming line and neutral conductors to the product 

under test.  This switch allows the line and neutral polarity to be reversed as called for in some 
Standards.  With 240 Volt operations, this switch swaps both sides of the 240 Volt line. 

 

C.  GROUND SWITCH: Controls the connection of the incoming ground line to the product under test.  

This switch allows the grounding conductor of the product under test to be disconnected as called 
for in most Standards.  The red Ground Open light illuminates signaling the potential for danger that 
exists when the product ground is disconnected.  The momentary Ground Switch must be toggled to 
“OPEN” in order to isolate the ground at the D.U.T. output receptacles. 

 

D.  METER DISPLAY: 3 1/2-digit LCD display that measures the true RMS value of leakage current. 

 

E.  POWER SWITCH: This switch controls power to the internal circuitry of the LT-952 only.  When the 

switch is ON, the meter display should be visible and the green Ground Closed lamp should be lit.  
For safety, the LT-952 is designed to disable both the front and rear panel outlets when the power 
switch is OFF. 

 
F.  D.U.T. OUTLET: Provides a convenient way to connect 120 Volt, 15 Amp products to the LT-952.  

There is no need for a rear panel cord-set adapter.  For safety, this outlet is disabled when the LT-
952 is set for 240 Volt operation. 

 
G.  GROUND INDICATORS: The Open Ground and Closed Ground indicators continuously display the 

state of the grounding conductor to the product under test.  The Open Ground indicator is colored 
red to signal possible danger in that the product's safety ground has been defeated.  The green 
Closed Ground indicator signals that the grounding conductor to the product under test is intact. 

 
H.  METER CONNECTION BANANA JACKS: Allows external connection to the meter measurement 

circuit as described under “Meter Connection Switch”  

 
I.  METER RANGE SELECTOR SWITCH: This Switch controls the sensitivity of the internal meter 

circuit.  The meter can be set to either 0-2 or 0-20 mA full-scale range. 

 
J.     METER SELECTOR SWITCH: Controls the connection of the meter measurement circuit to the 

product under test in the following manner: 

 
a. Surface-To-Surface - This selection connects both sides of the meter measurement circuit to the front 
panel banana jacks.  Leads connected to these jacks are used for measuring the leakage between any two 
surfaces on the product under test. 
 

 

b. Device Under Test Ground - This selection connects the device under test ground to one side of the 
meter measurement circuit.  The other side of the meter measurement circuit is connected to the meter 
reference.  The momentary Ground Switch must be toggled to “OPEN” while making measurements to  

Summary of Contents for LT-952

Page 1: ...PRODUCT SAFETY SOLUTIONS U US SE ER R S S M MA AN NU UA AL L L LE EA AK KA AG GE E C CU UR RR RE EN NT T T TE ES ST TE ER R MODEL LT 952...

Page 2: ...INTRODUCTION 2 Warnings 2 Product purpose 2 Understanding Leakage Current 3 Before using 4 PRODUCT COMPONENTS 5 PRODUCT SPECIFICATIONS 9 OPERATING INSTRUCTIONS 10 THEORY OF OPERATION 13 TROUBLESHOOTIN...

Page 3: ...HANDS AND FINGERS AWAY FROM ENERGIZED COMPONENTS AT ALL TIMES NO USER SERICEABLE PARTS INSIDE SERVICING BY QUALIFIED SERVICE PERSONNEL ONLY Product purpose The LT 952 leakage current tester is a stat...

Page 4: ...duct is properly bonded to ground the leakage current will ideally follow this path to ground However if the product is not grounded or is improperly grounded a person contacting the product may becom...

Page 5: ...e skin resistance Most Standards deal with these issues by lowering the leakage current limit for hand held products and products that may be exposed to moisture Furthermore it has been proven that th...

Page 6: ...ure 1 Front Panel A Neutral Open Closed Switch B Line Forward Reverse Switch C Ground Open Closed Switch D LCD Display E Power On Off Switch F D U T Device Under Test Receptacle G Open Closed Ground I...

Page 7: ...2 is designed to disable both the front and rear panel outlets when the power switch is OFF F D U T OUTLET Provides a convenient way to connect 120 Volt 15 Amp products to the LT 952 There is no need...

Page 8: ...r measurement circuit is connected to the meter reference This connection is used to measure the leakage between an exposed metal surface and the meter reference point WARNING Hazardous Voltage exists...

Page 9: ...utput connector is energized at all times when the LT 952 is connected to a power source A VOLTAGE SELECT SWITCH This switch configures the LT 952 to run off either 100 120 or 200 240 VAC The switch m...

Page 10: ...to 50 C Storage Temperature 40 C to 70 C Humidity 80 R H 0 C to 35 C Overall Dimensions 11 1 2 in W x 13 1 2 in D x 5 1 4 H in 29 2 cm W x 34 3 cm D x 13 33 cm H Overall Weight 9 0 lb 4 0 Kg Body Cir...

Page 11: ...cable 2 To verify that there are no other grounds to the equipment under test connect an ohmmeter between the ground pin on the product under test and the power system ground Readings of close to 0 O...

Page 12: ...area so that you or another person cannot accidentally come into contact with the product during the test Since the product ground is disconnected while the Ground switch is toggled OPEN the product...

Page 13: ...duct 7 Within a few seconds the display on the LT 952 should settle to the final leakage current value If the displayed result is less than 20mA operate the Range switch to the 2mA position 8 IEC60990...

Page 14: ...THE METER MEASUREMENT CIRCUIT THE RESULT IS EXCESSIVE CURRENT THROUGH THE METER THAT CAN CAUSE THE METER FUSE TO BLOW THEORY OF OPERATION This section of the manual contains a description of the circu...

Page 15: ...ence to the Meter Connection Circuit Meter Connection The Meter Connection Circuit receives inputs from the front panel banana jacks meter reference switch and ground switching circuit The front panel...

Page 16: ...not change test conditions while holding the Ground switch in the OPEN position This causes momentary transients that will blow the fuse Depress the Ground switch only long enough to take a measuremen...

Page 17: ...y Ground switch on the LT 952 must be toggled to OPEN Otherwise the leakage current is effectively shunted around the meter circuit to the ground REFERENCE STANDARDS 60950 60335 and IEC 1010 based Sta...

Page 18: ...and are able to generate technically valid results The exclusive use of calibration service providers which have been recognized by an independent accreditation body as conforming to the requirements...

Page 19: ...to the unit caused by excessive overload Furthermore this warranty does not cover damage caused by use of any attachment not original equipment of the product In addition ED D shall not be liable for...

Reviews: