Fan Motor

<body topmargin=0 leftmargin=0 marginheight=0 marginwidth=0> <table cellpadding=0 cellspacing=0 border=0><tr> <td valign="top" colspan=2 height=90 BGCOLOR="#006633" TEXT="#F7F7FF" bgproperties="fixed" background="079005a0ddvuru.png"> <div> <A HREF="http://www.vernco.com/index.htm" TARGET="_top" TITLE="http://www.vernco.com/index.htm"><U><B>home</B></U></A><B>     |     </B><FONT SIZE="5" COLOR="#FFCC66" FACE="Arial" ><B>Vern</B><B>co.com</B></FONT></div> <div> back to<B>  </B><A HREF="index.htm" TARGET="_top" TITLE="Harrison Heater"><U><B>Harrison Heater</B></U></A></div> <bR> <div> <A HREF="http://www.vernco.com/id173.htm" TARGET="_top" TITLE="http://www.vernco.com/id173.htm"><U><B>Site Map</B></U></A></div> <div> </div> </td> </tr><tr> <td valign="top" width=150 BGCOLOR="#669966" TEXT="#080000"> <div> <A HREF="id586.htm" TARGET="_top" TITLE="Heater Core"><U>Heater Core</U></A></div> <div> <A HREF="id583.htm" TARGET="_top" TITLE="Paint and Decal"><U>Paint and Decal</U></A></div> <div> <B>Fan Motor</B></div> <div> <A HREF="id584.htm" TARGET="_top" TITLE="Installation"><U>Installation</U></A></div> <bR> <bR> </td> <td valign="top" height=390 BGCOLOR="#FFFFFF" TEXT="#080000"> <div> The fan motor was stamped with the part number 5047606 from Delco Appliance of Rochester, NY.  The shaft barely turned by hand.  A good cleaning and inspection was in order.  Two bolts with nuts hold the motor together, and a second pair of nuts secures the motor to the heater case:</div> <bR> <div> <A HREF="id598.htm" TARGET="_top" TITLE="Fan Motor Throughbolts"><U><IMG SRC="9d6965a0.jpg" border=0 width="150" height="90" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> A small setscrew holds the fan to the shaft.  Clean up any corrosion or burrs on the exposed shaft before separating the motor case.  The shaft passes through a bronze bushing that could be damaged during disassembly if this precaution is not taken.  </div> <bR> <div> Normal wear and tear had taken a toll on the armature's commutator section.  It was cleaned up on a lathe.  This could also be done carefully on a drill press with strips of fine sandpaper.  The copper surface must be highly polished for proper operation:</div> <bR> <div> <A HREF="id600.htm" TARGET="_top" TITLE="Fan Motor Armature on Lathe"><U><IMG SRC="9da96630.jpg" border=0 width="150" height="99" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> The armature was unusual, with no mica between the commutator segments.  The cutting action caused copper burrs to bridge the open gaps.  The gap was too thin for cleaning with a hacksaw blade, so a feeler gauge was pressed into service.  To act as a cutter, the end of the feeler gauge was sharpened with a file.  The sharp edges of each segment were lightly broken with a needle file.  You only need to deburr, not create a bevel. Inspect carefully with a magnifying glass to make sure the debris is pushed out and not further into the gaps:</div> <bR> <div>   <A HREF="id603.htm" TARGET="_top" TITLE="Cleaning Armature Gaps"><U><IMG SRC="9dc96440.jpg" border=0 width="150" height="68" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> Two more checks are needed before the armature is ready to reinstall.  Visually inspect the connections at the commutator for evidence of melted and thrown solder, indicating previous overheating.  This can usually be repaired with careful resoldering.  If the wiring's varnish insulation has broken down, which is also likely with overheating, continuity will exist between the commutator and the shaft.  This image shows the correct lack of continuity:</div> <bR> <div> <A HREF="id601.htm" TARGET="_top" TITLE="Fan Motor Armature Continuity Check"><U><IMG SRC="9deaf540.jpg" border=0 width="175" height="84" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> The shaft rides on a pair of bronze bushings.  Small retainers are riveted in place to secure the bushings, but there is no need for removal unless replacement is needed.  The old crusty lube was cleaned with a Q-Tip and solvent.  The shaft would barely turn before, with cleaning and a couple of drops of fresh oil making a huge difference.  This view shows the armature reinstalled in the open motor.  The brushes had plenty of material left and did not require replacement.  Install the armature in the brush end of the motor before joining the two halves.  It is tricky to hold back both brushes while reinstalling the armature.  Unlike most motors or generators, there were no provisions for holding back the brushes during assembly:</div> <bR> <div>  <A HREF="id599.htm" TARGET="_top" TITLE="Fan Motor Exploded"><U><IMG SRC="9e0af770.jpg" border=0 width="175" height="119" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> The wires between the brushes and field coils must be folded carefully.  There is a gap on either side where the wires fit.  Make sure there is no paint under the through bolt heads to ensure a proper ground via the heater case.  Metal to metal contact provides the ground path between the laminated field core and the motor case halves.  Note the dimples on each case half which sandwich the laminated field core in place.  On the inside of the case halves, the edges of the dimples must be free of paint and corrosion to ensure a good conductive path:</div> <bR> <div> <A HREF="id602.htm" TARGET="_top" TITLE="Fan Motor Brush Wire Closeup"><U><IMG SRC="a2baf5a0.jpg" border=0 width="175" height="90" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> After assembly, a drill was used for several minutes to seat the brushes on the freshly cleaned commutator.  If the motor was energized right away, arcing could ruin the surface before the brushes were seated.  While not shown, the easiest way to hold the motor is by reinstalling it in the heater case.  To complete the break-in, run the motor unloaded (fan blade not installed) for several more minutes:</div> <bR> <div> <A HREF="id604.htm" TARGET="_top" TITLE="Fan Motor and Drill"><U><IMG SRC="9e4966e0.jpg" border=0 width="150" height="110" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> The ground path through the heater case is not very reliable.  The motor bolts to the outer case half, which is connected to the inner case half which hopefully makes a good ground when bolted to the firewall.  Not wishing to rely on such tenuous connections, I ran a direct ground wire from the upper through bolt.  The motor case was cleaned to bare metal under the wire terminal for a good connection.  The ground wire is routed next to the power wire and passes through the same grommet in the heater case.  In addition, the thin sheetmetal case amplified the sound of the motor and fan, so a vibration-absorbing washer was added between the motor and heater case.  Cork gasket sheeting was used for the washer.  I've seen heater motors covered in a material similar to autobody undercoating, most likely for sound deadening purposes:</div> <bR> <div> <A HREF="id625.htm" TARGET="_top" TITLE="Heater Motor Ground Wire and Washer"><U><IMG SRC="a5faf420.jpg" border=0 width="175" height="66" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <div> If you choose not to add such a ground wire, make sure there is metal to metal contact all the way to ground.  The nuts that held the motor to the case have serrations that cut through the paint when tightened.</div> <bR> <div>   </div> <bR> </td> </tr></table></body>