Hoover 475.

[Darren-UK]

Hi all,

I've just become the owner of a Hoover 475. It's a 1935 model, so quite modern really .

The second image shows an aperture in the front of the motor housing. I am aware some models of this type had a lamp in the aperture, illuminating a (or the) Hoover badge, whereas others did not. As there's nothing inside the aperture I am assuming this was one of those which didn't have a lamp.

Question is, on the lampless versions did something cover the aperture or was it simply left open?

Images on the internet of the lampless version are not clear, although indications are that the aperture was simply left uncovered. Can anyone confirm this?

Aside, this machine came fitted with a 5A Wylex plug and the mains lead is an original Hoover type, although I don't know if it's original to this particular machine.

TIA.

[Darren-UK]

Cancel much of the above. I've discovered this is the version with the lamp but the bulbholder's missing. The question still remains, however, of what, if anything, covered the aperture.

[twocvbloke]

Can't say much about getting the motor running, but, there's some info here on the machine:

http://www.vintagehoover.com/models543475.htm

If you contact the site owner (Jack Copp, (he was on the radio somewhere recently and in the Daily Mail because he landed a job at Dyson) he may be able to advise on how to repair it).

[Heatercathodeshort]

My mother had a 262 [1946] with a lamp but the opening did not have a cover. J.

[Darren-UK]

I kind of suspected there was no cover, partly from pictures and partly because there's no sign of any means of securing a cover to the aperture.

[Heatercathodeshort]

Remember you can file down larger brushes to fit. They are usually supplied with springs.
Try power tool spare suppliers. Just a thought. John.

[Mike Phelan]

Darren

What John says. Earlier Black and Decker drills had round brushes and I managed to get a pair for my drill from a local B&D agent a few years ago.
They are the sort with conical springs with a groove on the brushes to attach them.

[Darren-UK]

Yes, I was looking at power tool spares yesterday. Although I've not yet measured, the required brushes look to be around 10mm diameter (they'll be the Imperial equivalent I suppose) so possibly bigger than any electric drill would use. I'll keep searching though.

[Darren-UK]

Motor is now dismantled. First image shows where the mains input has been ripped out and the two wires twisted together. These had actually been pushed right inside the motor. The wires appear to be sheathed in something metallic and flexible.

As these wires disappear into the field coils, I've not yet got a clue how I'm going to repair them. They lead from the motor up to the socket at the base of the handle, inside a long coil spring thingy for protection.

Second question, what is the red resistor in the second image? It's marked '79 - something illegible' and appears to be in series with the field coils although it's hard to tell due to everything being cramped on the inside of the motor.

[twocvbloke]

The wiring should be mains into coil, coil to one brush, other brush to mains out, though you have to get the brush wiring the right way round or the motor will turn in reverse. It won't harm the motor though, but it'll tell you if the wiring is correct or not.

[Herald1360]

Component marking looks like 790ω which could be 790Ω in modern parlance.

Old style ω (lower case omega) = ohms, Ω (upper case omega) = megohms.

Check its resistance.....

It can really only be R or L if it's in series with something.

[Darren-UK]

It reads 805Ω.

[Herald1360]

That's within 5% of 790ohms, so it looks like it's a resistor. I've no idea of its design function, though.

Is it in series with a capacitor anywhere? (Thinking spark suppression).

[twocvbloke]

My guess on the resistor would be for the variable regional voltages of old, Hoovers were once upon a time made to order for a specific area's voltage, and after the power was harmonised into 240v AC across the board, maybe the resistor was added to drop the voltage to it's original factory made rating?

Spark suppression capacitors aren't in series on AC motors, they're in parallel, and I don't see how a resistor could be used for spark suppression...

[Herald1360]

I don't think that resistor's man enough for voltage dropping duty- it seems like too high resistance anyway.

I was thinking of a series R-C snubber, though a resistor in parallel with an inductor would limit the inductive kick voltage when switched (by the commutator) by providing an alternative path to the contact air gap.

[Lucien Nunes]

The resistor may be a voltage dropper for the lamp. Can you trace the lampholder connections?

Lucien

[Darren-UK]

General reply to the last four posts .

There's no capacitor fitted anywhere. Being a 1935 model it possibly predates laws on radio interference but I don't know for certain.

I've wondered if it was either to limit the kick at start-up or a voltage dropper/surge protector for the lamp. The motor data plate states "225 - 250V DC to 60 Cycles, motor no.4 P.M.".

I don't know if the "4 P.M." is just a Hoover part number or if it signifies use for a specific area. The "225 - 250V" pretty much dictates where the Hoover could be used though.

The coils are very well bound in some sort of heavy insulating tape and the wires to the lampholder and brushes emerge from within that binding. It's therefore visually impossible to trace the path of the lampholder connections. All that binding also makes any thoughts of tracing the wires via resistance readings a head-scratcher too, as there's few points I could take readings from.

Initial impressions are that the lampholder is tapped off the field coils, with the resistor in series with the coils but, again, all that tape makes it difficult to be certain. I don't fancy removing the coils and unbinding them either!

When it's daylight tomorrow I'll take some clear pictures. The motor is currently dismantled anyway, conveniently.

[Darren-UK]

Three images attached. First shows the connections to the resistor, second shows a general view including the two mains input wires at the bottom. These are the ones which have been ripped out and will be a fiddle to repair.

The third image shows the rear of the lampholder. This is a replacement I was lucky to find as the original was missing for some mysterious reason.

Anyway, as can be seen, tracing the wires from the resistor visually is impossible as they vanish behind, and seemingly into the mass of Egyptian mummy-type bindings around the coils.

I've just put the meter on it. From one resistor terminal to one terminal of the lampholder I get 818ohms and from same resistor terminal to other lampholder terminal I get 18ohms. Identical readings are obtained by doing the same but from the second resistor terminal.

It's therefore looking like the resistor is there for the lamp, presumably as protection against varying voltages/surges.

[Darren-UK]

Update, the old girl is now running again.

I ended up having to 'make' some carbons for the motor by cutting to length some other pair and using Wet & Dry to reduce the other dimensions. I also had to make a retaining clip for one of the brushes and replace the insulation on the wiring to the brushes. The motor bearings, still in good order, had to be thoroughly cleaned and regreased.

I had to replace the ripped-out cable from the handle to the motor. This was a pain as the original cable fed from the socket at the base of the handle, directly into the bowels of the motor. The job might have been easy if I could've removed the field coils. I couldn't, they were jammed solid in the motor casing. So I had to solder the new cable onto the surviving stubs of wire inside the motor and insulate with a couple of layers of heatshrink.

The new cable is 3-core, deliberately. I was able to attach a hidden earth connection to the shrouding around the motor and take the earth wire invisibly up to the base of the handle. Only the last inch or so can be seen where it attaches to the wingnut which clamps the handle in place. The handle is, in turn, connected to earth near the switch at the top.

The potential danger with these old Hoovers is that if a (carbon) brush retaining clip fails, the brush spring will push the electrical connection onto the motor cap and the whole thing becomes live. Even though the handle is earthed, I didn't feel the hinges of the wishbone, the latter being which the handle attaches, could be relied upon for a good earth connection.

I came across one curious fault. When examining the switch I discovered the live terminal was loose and the screw needed one complete turn to tighten it. The curious part is that the original dashes of white paint on the terminals were intact and undisturbed. I thus concluded that the terminal must've been like that when the machine left the factory 75 or so years ago. It's possible the switch is a later replacement but it is an original type and colour matched to the rubber handle grip so I assume it's original. The spot of paint on one of the switches mounting screws was also intact.

So that's it. All I've got left to do is find a suitable belt for the beater; those for the Junior range being far too small.

[twocvbloke]

The belt issue could be solved using a Hoover senior belt, but I'm not sure, I've never seen one of those Hoovers in person so I don't know what size they need, though I do know a local vac shop here in Colne sells "old style" Hoover upright belts, which are larger than the Senior belts, and thicker too, the only belt I know of that is of a similar diameter (but not thickness) are Sanitaire belts, also known as Eureka type RD belts (in the states & canada at least), which are sold here in the UK for the Electrolux C12, C16 and ZC-880 models, but there's no guarantee they would work, or even fit...

As you're in Blackpool though you could hop on a train from Blackpool South station and travel to Colne (£13.80 day return), I'd recommend a Wednesday or a Saturday, cos then the market is on up in the town centre near tot he shop in question, so there'd be something here to do at least (after getting the belt of course)!!!