Operang MH

<body topmargin=0 leftmargin=0 marginheight=0 marginwidth=0> <table cellpadding=0 cellspacing=0 border=0><tr> <td valign="top" height=45 BGCOLOR="#808080" TEXT="#080000" bgproperties="fixed" background="03f00700eowhpc.gif"> <div> <FONT SIZE="5" COLOR="#FFFFFF" FACE="Arial" ><B>Lighting Information</B></FONT><B>     |     </B><A HREF="index.htm" TARGET="_top" TITLE="Lighting Information"><U><B>home</B></U></A></div> <div>                                                   </div> <div> </div> </td> </tr><tr> <td valign="top" height=435 BGCOLOR="#FFFFFF" TEXT="#080000"> <div> Operang MH</div> <bR> <div> Operating Metal Halide lamps</div> <bR> <div> Standard metal halide bulbs should only be operated in enclosed fixtures (the arc tube may rupture for a number of reasons). The fixture must be able to with stand particles of glass at hot as 1000C.   </div> <bR> <div> Metal halide bulbs should be wiped with alcohol before operating.  The bulb should not be operated if the outer bulb is scratched.  Metal halide bulbs may explode from pressure while operating if the bulb has been scratched.  </div> <bR> <div> If the outer envelope is broken or missing, turn power off immediately.   If the bulb is still operating this can cause eye inflammation / skin burn from ultraviolet radiation. </div> <bR> <div> SOME bulbs (operated horizontal) must not and should not be operated with the exhaust tip (nipple) pointing down on the arc tube (see fig.1).  This depends on the bulb design and the manufacturer.  </div> <bR> <div>                                                                                    Fig. 1</div> <div>                         <IMG SRC="167da500.gif" border=0 width="218" height="80" ALIGN="BOTTOM" HSPACE="0" VSPACE="0">                    <IMG SRC="15fd9670.gif" border=0 width="217" height="103" ALIGN="BOTTOM" HSPACE="0" VSPACE="0">      </div> <bR> <bR> <div> If someone is unsure operate the bulb with the tip pointing any other position than down.  (Caution! Some bulbs have to be operated with the tip down.  These bulbs usually have a base that locks the bulb in the proper operating position.)</div> <div> SOME quarts metal halide bulbs when operated tip down (fig.2) can cause metals / sodium to collect in the tip.  The tip acts as a heat sink causing the tip to be the coolest part of the arc tube.  The bulb may not operate optimally because the metal / sodium is not even within the arc tube.  Some metal / sodium may even get trapped in the tip.  This is not true for all MH bulbs.</div> <bR> <div>                                                                                       Fig. 2</div> <div>                                                                    <IMG SRC="15dd0400.gif" border=0 width="208" height="64" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></div> <bR> <div> When operating the bulb with the tip pointing other than down ensures the mixture is even within the arc tube (after cooling).  The arc in the arc tube curves up keeping the tip hot.  This keeps the metals / sodium from collecting in the tip (during cooling).  </div> <div> <B>      </B></div> <bR> <div> <A HREF="id62.htm" TARGET="_top" TITLE="Trouble Shooting HID lighting"><U>Click here for trouble shooting HID lighting</U></A></div> <div>  </div> <bR> <bR> <bR> <div> Drawings and text by: Paul Erik Hirvonen</div> <bR> <bR> <bR> </td> </tr></table></body>