I helped my neighbor replace a motor on his boat lift. Usually these are the typical 6 wire motor on a drum switch. (4 wires to the motor) This one was still the 6 wire motor but there were only 3 wires to the motor. After a lot of head scratching and looking into the controller, this is what I figured out. Does this look normal? It does work.

It's new to me but I can't see why it wouldn't work.

I found this boat lift motor diagram that looks like it may similar be what you have.

Lift Motor Wiring

Greg:
I had one for a 'friend' on the bay side of the barrier island. He took it apart, & tried really hard to see how bad he could screw it up. Wound up exactly as your diagram & works well.

That is the normal 4 wire thing you see on the Furnas site for a drum switch.

They are doing this with 3 wires. The difference is the start winding is in series with one of the run windings.
I haven't noticed any loss of starting power but it has to be getting less "kick".

John, let me guess, this was a remote control lift?

I drew the controller as a DPDT switch just to show how the logic works. It is really done with a box full of relays. I am still not sure why it is done this way. They still have 2 relays per direction. My guess is the original design was one relay each way but that would have left one side energized. (as my picture is drawn)

Greg:
You got it! A strange setup, but it works!

He was an office guy, that likes to think that ECs make to much $$. He changed his outlook when I lifted his week old Pursuit up & down! He was playing with the wiring for two days before the 911 call.

Looks good to me.

Windings #1-#2 + #3-#4 are the Split Coil Main (Run) Windings.
The Winding at Terminal #8 is the Auxiliary (Start) Winding, which is in Series with the Start Capacitor and the Start Switch. Start Switch Terminal is #5

Appears to be a Dual Voltage ("Low Volts" = 120V, "High Volts" = 240V) 1 Phase Capacitor Start Induction Motor, setup for "High Volts" (240V) Input.

The Auxiliary "Start" Circuit (Winding, Capacitor & Start Switch) connects to the "Center Tap" point of the Main "Run" Windings. This results in 1/2 the Motor Terminal Voltage across the Start Circuit - or 120V.
Look sort of familiar??? Works the same as the 120/240V 1 Phase 3 Wire Transformer feeding it!

With the Start Circuit connected via the Center Tap, the Capacitor may be rated for 120V, even though the Run Windings may be connected across 120V or 240V.

As to the Connections Scheme, the "Key" to proper connections (per "Forward" and "Reverse"), is to "Make" the Start Winding reduce the Mag. Field Strength on One "Side" of the Run Winding.
This is what determines the Startup Rotation.

Using Greg's Schematic example above, Connecting the Start Circuit Terminal #5 to "L2" will start the Rotor in the Counter-Clockwise Direction (normal "Forward" direction).
The Start Winding reduces the Field on the "Lower" Winding Section (#3-#4), causing the Rotor to "Fall" in that direction.

Connecting the Start Circuit Terminal #8 to "L2" will start the rotor in the Clockwise Direction ("Reverse" direction).
The Start Winding reduces the Field on the "Upper" Winding section (#1-#2), causing the Rotor to seek that direction.

BTW, if this Motor is a PSC (Permanent Split Capacitor) type, no Centrifugal Start Switch will be included in the Auxiliary Circuit, and the Auxiliary Circuit is always connected to the AC Input during Motor Operation.

-- Scott

This is what the manufacture has in his instructions so you can see it was hard to make the leap to what they had.

A+ to the guy who figured out the wiring the way you found it. I wonder about the instant reverse switch, though.

I am not sure what the instant reverse switch is all about but my guess is it drops out as soon as power drops so you don't have to wait until a centrifugal switch drops.
On my lift with the normal motor, reversing it doesn't do anything until you hear the switch drop out.

Greg,
Actually what I'm seeing there with your diagram is a capacitor start motor, the capacitor feeds the start winding, until such time as the centrifugal switch opens at 70-75% Full load speed.
After that, the two run windings do the work.

Oddly enough, what voltage is this motor?
With it having a lift on it, you'd think there'd be some sort of a gear-box attached to the shaft of the motor.
First thing I would do before installing a new motor is strip down the gearbox and make sure everything inside is sound.

With respect to the relay box, it sounds to me like they needed to cascade relays, instead of installing a contactor.
This is often done to carry the switching current in forward/reverse situations.
It is the poor mans solution.

Mike, the "gearbox" is one pinion gear about 4-5 cm, driving a big ring gear maybe 30cm and the pinion gear is belt driven off the motor with a similar reduction so there is not much to inspect.

I agree the control box is probably not what I would make but it does seem to work. The one I have runs off a garden variety drum switch.

His lift is 240v, mine is the same lift tapped for 120v.
He has 2 lift plates, I just have one. I never planned on being able to afford that big a boat
It also lets me share the circuit with the lights and a receptacle on the dock. I imagine you could run 2 3/4 HP motors on 120v 20a tho.

Looks like some type of Plugging Control, or

-- Scott

The effect is if you flip the motor into reverse, it reverses, instead of keeping going the same way.
Evidently it is not a centrifugal switch.

The way the "Instant Reverse Switch" is shown in the Schematic, along with the Positioning in the Auxiliary Circuit, should be for Plugging the Motor.

***FYI***

For those unfamiliar with the term -Plugging-:

"Plugging" is a Motor Control term for rapidly stopping the Motor by Temporarily Reversing the Rotor's direction.
This is achieved by momentarily connecting the Motor, so as to run in the opposite direction - resulting in a very rapid stall.

"Anti-Plugging" Control would be used to stop the Motor "Normally", then automatically start in the reverse direction.

-- Scott

Thanks Scott, that was a new one for me.
I have seen schemes that shunted the windings of a motor to stop it faster, usually with mechanically interlocked relays.

Plugging is normally associated with Life Safety events.

It's brutal on the windings -- so much so that the typical motor can be ruined by its first plugging event.

However if plugging will stop a train from plowing into another... so be it.

A collision will surely ruin all.

You don't get an instantaneous reverse with a 1-phase motor.

Plugging is a 3-phase phenomena.

A reversing switch in a capacitor start motor needs to re-engage the start windings and get the field in proper sequence.

So it goes Left-Stop-Right. Never Left-Right like plugging a 3-phase motor.

I will go play with this lift again when I get the chance but I think I saw this thing flip directions before it stopped. It hummed a second and went off the other way. I didn't really see it all put back together. Once we got it wired I went back to my project and let him finish it up.

Tesla,
If plugging is what I imagine as "inching", you can use that with any single phase motor, all it takes is a motor with a reduction drive and controls that have momentary switches, for things like up or down.
They also have a COD (Change of Direction) contactor, with an adjustable timer to make sure that the gearbox has stopped turning before the motor starts heading the other way.
With worm drive gears this is very important.

A 1-phase machine whose connections are flopped while running -- with the start windings no longer connected -- will treat the wave change as if the induction rotor 'slipped' and then simply keep on spinning in the same direction. This is an inertial effect.

To get a 1-phase to reverse the start windings need to be re-engaged -- hopefully after the speed drops to zero.

3-phase machines will violently reverse torque when plugged. It's an ugly thing.

About 7 years ago I connected a pair of 5 h.p. vibrator motors that need to be plugged to stop them real fast. When they shut down they coast for about 3 seconds then get 3 seconds of reverse rotation. After stopping at least once per day for that many years, it seems normal, except reverse rotation has over-sized overloads and they occasionally trip.