Running 12" BAO/S Planer Thicknesser with inverter drives

[MilesH]

Does anyone have any experience or advice on this?

I'm thinking of buying one but I only have a single phase supply.

According to the manual, the cutterblock motor is a 3hp Brook motor. Not sure if you can change to Delta phase connection in the terminal box, or not. If not, it means opening up the motor or using a 240v in 415v out inverter.

The drive motor is a Brook T14 2 speed motor. I guess this one is more challenging......

 

[MilesH]

This is the wiring diagram for the drive motor.

 

[wallace]

If your using a vfd on the drive it doesn't matter if its 2 speed because you will only need one speed and then use the vfd for altering the feed.

 

[MilesH]

Indeed. I quite like the idea of an infinitely variable feed... Still need to set it up correctly though. There might be some advantage in retaining the switching? Even though you couldn't change with the motor running.

 

[MilesH]

Never had a 2 speed motor before. This seems to be the principle: https://en.wikipedia.org/wiki/Dahlander ... ging_motor

 

[MilesH]

So, for the high speed, the phases are connected in Delta configuration.

If I just retained this connection and used a 240v output inverter, I would get a base speed close to the original lower feed speed (4.5m/min.)

 

[deema]

I may be wrong, but I believe the machine has two motors, one for the cutter block and another for the feed. You will need two inverters to make the machine wok, you cannot operate two motors from a single inverter.

There are threads on the internet that suggest that running two motors simulateously from an inverter can be made to pseudo work....which is feasible. However, I would like to suggest that this resides in the school of thought that feels it’s acceptable and practical to use a six inch nail for a fuse, or match sticks to hold bare wires into a mains outlet socket.

 

[MilesH]

Yes, I'll definitely need two inverters! Hopefully, both 240v output or it will be an expensive exercise.......

 

[deema]

Looking at the wiring diagram all of the leads for the feed motor coils are brought out to the starter / switch. It’s highly likely that the cutter block motor is a 415V star configured motor. For this you will need to open up the motor and find the place where the coils joined together and bring out the leads.

I would check the cost difference between changing the motors and switch gear to single phase versus two inverters. I suspect there will be almost nothing in it. When you come to sell / upgrade it a machine with single phase motors seem to have better resale value than one with inverters.

 

[MilesH]

It’s highly likely that the cutter block motor is a 415V star configured motor. For this you will need to open up the motor and find the place where the coils joined together and bring out the leads.

I fear you're right about that. My Wadkin AGS sawbench, circa 1978, has a 415V motor with no way of reconfiguring to Delta in the terminal box... I'm running it on a static converter. On the other hand, I came across a photo of a motor on a BAO in Canada that seems to be dual voltage. Export only, I guess.... Ref: https://forum.canadianwoodworking.com/f ... hicknesser

 

[MilesH]

I would check the cost difference between changing the motors and switch gear to single phase versus two inverters. I suspect there will be almost nothing in it. When you come to sell / upgrade it a machine with single phase motors seem to have better resale value than one with inverters.

Thanks. That's certainly worth considering. Might even get an exact match with secondhand motors.... Single phase BAO/Ss do come up occasionally too but, as you say, usually at a premium. I'd be stuck with a single feed speed too...

 

[MilesH]

Drives Direct do a 2 stage inverter that outputs 415V 3phase from 240V single phase input: http://www.drivesdirect.co.uk/Products/ ... 40_415.htm Twice the cost, too.....

 

[Myfordman]

Drives direct claim that it is just fine to run multiple motors from a single inverter but there are a few snags
1 If you use the inverter to modify the feed speed, the cutter speed will change too so the number of cuts per inch (and hence surface finish) won't change but simple alter the duration of the pass.
2) The inbuilt protection circuitry in the inverter will not protect properly the smaller motor. The work round for this is to buy a thermal overload* rated for the small motor, fit in series with its supply, then use the output to switch the inverter off using its low voltage logic inputs.
*£12 post free from toolsatan.

 

[MilesH]

Thanks. That's interesting to know. If one could retain the 2 speed switching, it would be a solution but I'm not sure you save that much money by using a single inverter over separate ones.

 

[MilesH]

Invertek have quite a good range. They do a 4kW model with single phase input.... https://www.motorcontrolwarehouse.co.uk ... 0.html?p=2

 

[Myfordman]

Invertek have quite a good range. They do a 4kW model with single phase input.... https://www.motorcontrolwarehouse.co.uk ... 0.html?p=2

I don't believe Invertek do voltage step up inverters?

Drives direct do internal modifications to standard 415 in 415 out inverters for the ones that they sell.

 

[MilesH]

I don't believe Invertek do voltage step up inverters?

Drives direct do internal modifications to standard 415 in 415 out inverters for the ones that they sell.

No, unfortunately, they don't. Drives Direct do a 3Hp 240V in 415V out (modded, as you say) but that wouldn't be be big enough to run both motors. AFAIK, the only larger ones are in their "advanced" range and prohibitively expensive....

 

[Myfordman]

I don't think there is an obvious solution although you are possibly making it harder by wanting to have continuously variable feed speed.
I don't find any need to tweak the feed speed on my thicknesser. It has two geared speeds and sits in the low speed permanently.
Whilst I'm a fan of inverters, a second hand static converter might be your cheapest option. Something like a quality brand transwave and be prepared to replace some of the capacitors as often used ones have suffered a bit but replacements are quite cheap. Stay away from Clarke! The only downside of a converter is that the inrush current on starting can be very high so you need a good low impedance supply to the workshop. An inverter is much more benign towards the supply and can be programmed to have a gentle start up. The inertia in a cutter block is high and can make starting a problem - in fact a planer is one of the most challenging types of three phase machines to start from a single phase supply.

Good Luck

 

[MilesH]

I've run my Wadkin AGS on a Transwave static converter for years. It works well but you certainly can't achieve the rated motor power with it... I used to have a BAO thicknesser in my first workshop, where I had a 415V supply to run it on. I wouldn't want less power than that.

Continuously variable feed speed only because you can, really The slowest of the 2 feed rates would be fine for me too. That and an even slower one on a switch would be ideal.... Could one just run the feed motor, as is, on 240V 3 phase? It's constant torque, not power, that you need for the feed drive.... Might need a separate fan, I suppose.

You're certainly right that there's no straightforward solution!

 

[Myfordman]

My approach would be to open up the star point in the cutter motor and convert to 3 phase 240v.
Use high temp wire - consider stripping out a bit of immersion heater wire as a source. Heat shrink sleeving on the joints and lace in the wires with nylon tie wraps.
Get a 240v in 240v out inverter to power it.
For the feed motor, look out for a step transformer to get a single phase 415v supply use this to power a 50% over rated* 415-415v inverter for the feed motor. arrange to only switch over speed using the dahlander connection only when the feed inverter is stopped.
Pick up the kit you need by scouring eBay.
* this is needed as you will only be driving it with single phase and so the internal capacitors need to be that much bigger than when the source is 3 phase.

hth