Excessively hot exit air flow can be an indicator of low air flow possibly due to partially blocked intake for the air where you won't feel the heat or something missing or assembled wrong that is part of the design for air to flow well or intrinsic to the design or a combination of those factors. (Do all other users of this same power tool have the same problem?) Otherwise, it can be indicative of voltage drop as in long extension cords and or thin conductors in the extension cords. For power tools, it's best to avoid excessively long extension cords or thin ones. If you have a lot of your extension cord coiled up while using it, then get a shorter one. If it's thin, get a thicker one. If you aren't sure, then try it. You can always go back to what was really sufficient. But, there is never harm in overkill in extension cord capacity. I prefer that. Why have a lightweight cord when you aren't holding it's weight in your arms while working? For my expensive polishers, I use this one from Autogeek: FLEX 50 ft. 12/3 SJTW HD Extension Cord with Lighted Plug. I figure my polishers have moving parts and life expectancy is related to running it cool and voltage drop is a big significant factor that you can easily control and for a very small investment in the increased power tool life. The electrical nature of power tools is that they will draw more current when the voltage is lower. A poor plug connection or an insufficient extension cord will give you voltage drop causing the power tool to draw more current and that causes more heat to be produced which could exceed the ability of the cooling air flow to remove sufficient heat resulting in the motor running warmer. Also, excessive current causes reduced brush and armature life. To a point, more current within normal parameters is fine, but at some point the higher temperature will shorten the motor life. Another factor that causes a motor to produce more heat is a higher load which is putting more pressure on the pad than is best for the motor. Learn by variation of the pressure to hear and feel the speed reduce. It's fine to have some small percentage of motor speed reduction with it doing work compared to spinning freely, but bogging it down to a significantly lower speed both lowers the fan speed for less air flow as it also increases the current draw to produce more heat since a motor draws more current when under load and at excessive load it can draw too much current for normal operating temperatures. Another factor that can compound this problem is selecting a low speed when you are also bogging down the motor speed even more. This is because the motor produces significantly less power at low speed and is more easily bogged down with pressure or load at low speed and that is further compounded by the fan on the motor also running slower to be producing less air flow for less cooling. An unlikely factor that I wouldn't suspect yet is still possible though not for quality products of trusted manufacturers is a design compromise with a undersized motor by design that is pressed into service that pushes it's limits for either cost savings or to have the advantage of a lighter weight tool. It could be a combination of any of these factors, so understanding what contributes to motor heat or more motor life will help us eliminate unnecessary hardships for the motor sometimes as easily as noticing where we place or hands or changing to a more appropriate extension cord. Also, similar to voltage drop, but worse comes from what many pridefully think of as their cleverness in believing that putting a twist or bends in the prongs of a plug is advantageous in increasing plug retention to not have an annoying pulling out of the plug from the extension cord. This "cleverness" causes a cascade of problems as it springs the mating contacts open more and requiring ever more bending to continue to achieve good plug retention. Then the plugs that haven't been so cleverly damaged to damage the receptacles will not have adequate retention. This necessarily forces others to do the same or get pullouts and intermittent electrical contact until someone like me causes a rule change to put a stop to it which also requires replacing all damaged outlets and cord ends. When two or more people think they are clever in doing this they compete with each other for their plug to achieve more retention causing an ever increasing cascade of damage to every extension cord and outlet they use. Never do that. Instead, find an alternative. A good one is ordering your power tool with the extra long cord. Another that causes no harm is taping the plug to the extension cord. If your extension cords are damaged by being sprung loose and the same for your outlets, then they are causing damaging intermittent and sometimes rapid on and off of the power tool. You can often feel this in variations in the smoothness or actually feeling it having glitches of no power. This is very damaging to power tool motors because it draws the most current at startup. If that is essentially happening many times a minute while you are using it, then solve that problem. Extension cords cost a lot less than replacing power tools. Replacing a loose electrical outlet is quick and easy and the outlet most often costs less than a dollar. Don't let those inexpensive things cost you in reduction of life of your expensive power tools.
