UL 746E Section 19 covers requirements for conformal coatings used instead of electrical spacings to increase the dielectric withstand voltage between traces on a printed-wiring board. Paragraph 19.3 outlines a Voltage transient test to be applied to a specific test pattern allows testing to determine spacings. The Surge Generator circuit is specified in UL 746E, Figure 19.2 is contained in the MegaPulse 746E. One press of the MegaPulse 746E TRIGGER button conducts the test suite as described in UL 746E, Para. 19.3. Note: Voltages 400V and over are certified to be in accordance with the tolerances of IEC 1180-1, Para. 6.2.2. Provided with external interlock control. In addition, for automated testing, the MegaPulse 746E is available with TestMinder, our computer control and test reporting option, and Arc Detect, which can detect and report an insulation failure. When both of these options are ordered together, the computer-generated test report will advise which tests passed and which failed. 
 

ITEM	NAME	FUNCTION
1	VOLTAGE Adjust Knob	Adjust the voltage set point in the tester. Turn Clockwise to increase the output voltage after the CHARGE button has been pressed. Turn the knob fully counterclockwise (lowest voltage setting) before the start of each test, and afterthe end of each test.
2	POLARITY switch	Toggles  the output pulse polarity from Normal to Reverse, Normal for positive and Reverse for Negative, The pulse will appear on the Output jack relative to the return jack The polarity switch only operates when the CHARGE indicator is lit and the voltage on the display meter is less than 180V.    The polarity is Normal when the NOR indicator is lit and, Reverse when the REV indicator is lid.
3	NOR REV indicator	Indicates the state of the Output Polarity switch.   NOR indicates Normal (Positive) position.   REV indicates Reverse (Negative) position.
4	CHARGE switch	Starts the charge process of the tester capacitor. The CHARGE indicator will turn off after the CHARGE switch is pressed, and the TRIGGER indicator will turn on. The charge process will stop after 2 minutes if the TRIGGER button is not pressed.
5	CHARGE indicator	This Yellow indicator is lit to show that pressing the CHARGE switch is the next logical step in a test sequence. CHARGE indicator is lit when the tester is turn ON an after pressing TRIGGER button. CHARGE indicator will go out after pressing CHARGE button. CHARGE and TRIGGER Indicators will be blinking if the Interlock Switch is open. (Only testers with Interlock SwitchOption)
6	TRIGGER switch	Triggers the output impulse waveform. The impulse waveform will appear across the output leads.
7	TRIGGER indicator	This Red indicator is lit to show that the tester can be trigger. TRIGGER indicator is lit for 2 minutes after the CHARGE button is pressed. TRIGGER indicator will go out after pressing TRIGGER button. TRIGGER and CHARGE Indicators will be blinking if the Interlock Switch is open (Only testers with Interlock Switch Option) TRIGGER  indicator  will  blink  at  when  the  Voltage.  This  effect  will  remain  on  until  the  TRIGGER  switch  is  pressed.  (Only testers with PC Interface option)
8	VOLTAGE meter	Displays the output voltage set point. The  voltage  reading  will  increase  from  zero  to  the  voltage  set  point  when  the  CHARGE  button  is  pressed.  Note  that  the Voltage meter may indicate that some residual voltage is present on the main storage capacitor, even when the tester is first turned  ON.  This  is  due  to  inherent  charging  of  the  internal  capacitors. Pressing  the  TRIGGER  switch will discharge the capacitors.  Note that the peak amplitude of the measured output waveform is proportional to the voltage that is read of the front  panel  of  the  MegaPulse,  but  it  will  always  be  somewhat  lower.  This is  because  the  meter  on  the  MegaPulse  is measuring the voltage on the main impulse storage capacitor. This voltage will intentionally dissipate to some extent before reaching the output leads.   The meter will start to flash at 12210V to indicate that voltage is in the maximum limits. If unit includes PC Interface and the Keyboard is locked, the display will show OFF when a button is pressed.
9	OUTPUT jack	The impulse waveform appears on the OUTPUT jack, referenced to the RETURN jack.  When the POLARITY switch is in the  Normal  position  (NOR  indicator  is  lit)  the  output  will  be  a  positive  pulse.    When  the  POLARITY  switch  is  in the Reverse position (REV indicator is lit) the output will be a negative pulse.
10	RETURN jack	This is the return for the impulse waveform.  This jack is referenced to the chassis of the MegaPulse, and is referenced to earth ground as long as the MegaPulse is properly grounded.  Even though this jack is referenced to ground, it should be treated as hazardous whenever the MegaPulse is turned ON.
11	LINE OUTPUT switch	When switched to the ON position, 120V line voltage will be present on the output leads.
12	EXTERNAL TRIGGER	The External Trigger Signal on the front panel is approximately 13 volts. In order to catch the correct signal the oscilloscope trigger level must be set to at least 10 volts.