All that I know . . .
The C-5 is a rare model made from about '59-'61, the only Compact with three wheels. It is famously misidentified in Tri-Star’s own history poster as a C-6. Models before the C-5 had two rear wheels and two front skids, while models after it had four wheels.
I have a C-2, C-5, C-6 and TriStar C-80-2 (two speed model). All except the C-2 were built in Anaheim, while the C-2 was built in Interstate’s old El Segundo factory. According to the plate or molding on the underside of the vacuum, the C-2 motor is 540 watts (aka 4.7 amps at 115v), the C-5 is 6 amps, the C-6 is 7 amps and the C-80-2 is 7.5 amps, all without powerheads. I know some of the TriStar DXL models had a 9.5 amp rating, again without the powerhead, though I don’t think they all were this high.
Regarding the C-5 powerhead, this was the famous ABC or “Always Beauty Clean” unit. These are incredibly rare so don’t count on finding one ever. Clearly Interstate intended to move a lot of these as many C-5s and even a few early C-6s had the power port on the right upper side of the vac body but it seems as if they didn’t have the powerhead available in quantity. Maybe someone more knowledgeable than me knows the whole story on the ABC. Interstate may have been affected by the Lewyt debacle where Lewyt came out with an early motor-driven powerhead in the late ‘50s that worked well initially but once the vac’s motor had worn it was possible for the powerhead electrical supply to shock the user. That caused lawsuits, sunk Lewyt and gave motor driven powerheads a bad name in some circles. However, Whirlpool/Sears and Electrolux were other early powerhead adopters that used a safer design (IIRC Whirlpool even before Lewyt) and they all continued to market them.
After the very early C-6s Interstate didn’t even put the powerhead port on Compacts, instead they offered an air turbine brush on C-7s as an option. This is similar to NuTone’s unit but has “Cyclonic” written on it. With the C-8 in the late ‘70s they got back into powerheads in a big way but the power port is at the bottom front of the vac between the two front wheels (pretty much where the single front wheel is on the C-5). It should be possible to adapt another powerhead to the C-5 but the OEM type Compact/Tristar electric hose will need to modified since the electrical cord on the vac end is intended to just be long enough to plug into the lower front location and I doubt it would stretch all the way to the upper right side where the port is on the C-5. Should be simple enough but will take some splicing.
Given the rarity of the C-5 it might be easiest to just pick up a later model off eBay with the powerhead, hose and tools and keep the C-5 for when you don’t need the powerhead. One thing about most any old canister vacuum is that it is much easier to get the vacuum than the tools, in particular wands and floor tools; for some reason people hang onto these when they sell the vac. So I’d look for a C-8, CXL or DXL with the tools, hose and wands included. It’s much cheaper to buy this way than trying to piecemeal individual items. With the C-7 Interstate switched from friction lock tools to button lock tools but the hose end at the machine is the same so you can use the later hose and tools with the C-5.
Pic is of a DXL from eBay, the most powerful original style TriStar I've ever seen. I'd love to have one of these!
