Startrite 275 Table Saw Conversion: 3 phase - Single Phase

[Ozark]

Hello all,

First post. I may be getting my hands on a Startrite 275 Table Saw from a generous benefactor.

It currently has a dual voltage 3 phase motor (240v Delta, 415V Star). An electrician is looking it over to see if it can be converted to work off single phase 240v.

I have read some of the very good threads on this site concerning this conversion.

3-phase-to-single-phase-startrite-275-conversion-from-3-ph-t91106.html

and

startrite-tilt-arbor-circular-saw-t88484.html


I have a question on the Startrite manual (found on web). See attached.

You could get the impression (probably badly wrong) from reading the manual that the machine can be made to work in either single phase or 3 phase by simply rearranging the wiring on the starter. What is not being disclosed here. Is the manual written to cater for two different motors, one single phase and the other 3 phase?

Edit: Can't attach pdfs or docs so I have attached some jpegs and added the detail below on the electrical connections


CONNECTION TO THE ELECTRICITY SUPPLY

IMPORTANT: Check that the electricity supply is suitable for the machine. At all times, ensure that the machine is isolated from the mains supply before making any electrical connections or adjustments.

Fuse and cable recommendations given in the chart below are intended as a general guide only, as local regulations and/or operating conditions may require alternative specifications to be adopted.
Motor full load current may vary according to constructions. The actual full load current is marked on the motor.

*** Chart ***

Connect the machine to a fused isolator of suitable capacity (see Chart above) using cables encased in conduit. Temporary connection (i.e. for demonstrations) may be made with flexible cables, provided that it is protected from accidental damage.
To connect machine to mains supply, proceed as follows:-
Remove cover of starter (four screws).
For single phase supply, connect two supply leads to top terminals L1 & L3 of contactor (see Fig. 1).

** Fig 1 ***

For three phase supply, connect three supply leads to top terminals L1, L2 & L3 of contactor (see Fig. 2).

*** Fig 2 ***

An adequate earth continuity lead (yellow/green) must be connected to the earth terminal of the starter.

IMPORTANT: IN ALL CASES THE MACHINE MUST BE EFFECTIVELY EARTHED.

The contactor incorporates an overload release and it is essential that it is set correctly in order that the motor is protected against sustained overload. The pointer on the overload unit must be set to include the full load amps of the motor.
A three phase motor may run in either direction, therefore, check that leading edge of saw blade passes downward through the table (see Fig. 3). If necessary, interchange any two supply leads to reverse motor rotation.
With all connections made, replace starter cover.

 

[flh801978]

That's just for changing between 415v 3 phase and 240 single phase
If you have a 3 phase motor you still need 3 phase
Vfd' or static or rotary converter needed
Or change motor to a single phase one

 

[Ozark]

That's just for changing between 415v 3 phase and 240 single phase

By this line do you mean that

This is what you do after you have switched out the 3 phase motor for a single phase.


I understand in principle the other options of getting the 3 phase motor to work from single phase using an inverter or converter as detailed in the other threads.

Thanks

 

[Ttrees]

Hello
I've got a Startrite 275 that I run with an inverter.
No need to have an electrician to wire it up.
The only thing you need to do to the motor is configure it to low voltage delta mode.
That is all there is to it.
In the terminal box on the motor there is 6 terminals, there will be 3 straps
In high voltage STAR mode, one of these straps is stacked on the other.
Rearrange these so all three are joining the other row.
Then it becomes DELTA low voltage mode

Now buy a VFD for £100 and wire it up
Order some switches from China now while your waiting
NC (Normally closed)for stop and NO (normally open) for on.
These should be got for about £5 for both.
Make/find a box for the VFD
Done
I can probably get or take some more piccys or other stuff if ya need.
Good luck
Tom

 

[flh801978]

Yes its just the way of wiring the starter for different motors/phases number off

 

[Ozark]

Hello
I've got a Startrite 275 that I run with an inverter.
No need to have an electrician to wire it up.
The only thing you need to do to the motor is configure it to low voltage delta mode.
That is all there is to it.
In the terminal box on the motor there is 6 terminals, there will be 3 straps
In high voltage STAR mode, one of these straps is stacked on the other.
Rearrange these so all three are joining the other row.
Then it becomes DELTA low voltage mode

Now buy a VFD for £100 and wire it up
Order some switches from China now while your waiting
NC (Normally closed)for stop and NO (normally open) for on.
These should be got for about £5 for both.
Make/find a box for the VFD
Done
I can probably get or take some more piccys or other stuff if ya need.
Good luck
Tom

Thanks Tom

Would you mind posting some details of the VFD you bought.

 

[Ttrees]

I bought a Huanyang 2.2KW vfd
I think there's newer ones slightly smaller, I chose the older design witch has an enclosed heat sink.
(the big aluminum thing on the back)
My saw runs off a 13A plug as I have a beefy wire going to house consumer unit, which as a 30A MCB.
No probs.
Delivered in a few days, I can get you some links for the switches I bought.
I ended up using some switches I had allready
The panel of timber is a paddle for a stop switch.
I made a steel box for mounting the switches.
You won't be using the original switches with a VFD.
The switches you need are the most basic as the VFD takes care of the no volt release function.


The most work is making those boxes

I will mention the relay on the newer one I got, stopped working after disconnecting the unit to check some motors.
I just replaced the front panel with the old one I have.
I damaged the old one on the bandsaw by bogging the saw down trying to cut with a damaged blade.
Dont keep pushing a bogged down motor down on these things folks!

I will give you the parameters for the VFD if you need
Tom

 

[dzj]

How much does a 2.2KW 3000rpm single phase motor go for in the UK these days?

 

[Ttrees]

I would expect a lot more, plus you would have to get switchgear also.

With a VFD you can program in a ramped startup also, which is probably a good thing
for your electrical requirements,
but also since the Startrite is a wee bit on the flimsy side for having a functional zero clearance insert.

 

[Ttrees]

I should have stated you need to have an MCB type breaker in your CU (consumer unit)
These are the most common and have been for ages, so its probably no issue.
What you don't want is a RCD breaker in your CU, as there is a phantom earth that will trip an RCD.

I am getting good use from my tablesaw with this device
Tom

 

[Ozark]

Please post as much as you can Tom.
I'm no electrician. The most I have done is extend a lighting circuit and a socket circuit.
I haven't even seen the saw in the flesh yet and to be honest I hope the electrician who is looking at it at the moment manages to sort it out.

 

[Ttrees]

Here's a few piccys
I think it's worth the risk with the Huanyang.
I was takin the pi** with the bandsaw, that's how the other one failed.
I have been giving the VFD on the tablesaw a good going over.

I believe the other VFD's to be more expensive.
I'm not sure how much a Teco FM50 or equivalent is, but I believe a UK brand "Invertec" 2.2KW inverter
costs something like 400 quid (I have not checked)

All I done to get this saw up and running is as follows ...
Got 2 meters of 4 core wire from the electrical shop, your needs may vary depending on the distance of your
saw to VFD
(If VFD is too far from motor it will emit noise, possible radio interference, )
Get some crimp connectors while your there...

So
3 core wire and the 13A plug
4 core wire for VFD to motor
You need 7 connectors to fit (or make fit) into VFD terminals (small fitting)
You need 4 for motor terminals
Another 2 connector for the earth for handiness (you could just stack both earths together, but Its easier to
join earths so you can fit into VFD terminal)

When you want a start and stop switch
(called 3 wire control)
These connect into the other row of small terminals
You need to get really thin wire (doorbell wire or similar) to go into very small terminals
DCM, RST, FOR terminals....Its very simple, I won't try explaining just yet...
You need a start NO and a stop NC button
The cheapest you can find.
I said I made my own housing for these switches..
I wanted the off switch out of the way and hands free too.
There is a dowel on the paddle which presses the off button, while there is a hole beside it for on as a safety mechanism.
I can choose the time it takes for the saw to stop, but choose to have it coasting for a few seconds extra.
(no unnecessary usage on the in built braking capacity), anyway
If its too fast it can loosen the arbor nut for the blade !
Other VFD's have parts (missing from most HY VFD's) to enable faster braking or braking under more loads

Make sure all dust entry points are sealed, I used the rubber insulation (wrap?)from a thicker wire for terminal housing once.


When this is all wired up enter in the parameters on the VFD
Remember to enter the parameter reset on these before you start programing.
1 minute doing that and its stored.

Get some crimp connectors to practice on
Make the VFD housing shiny for sawdust not to build up on.

Thats 10 to 15 quid for the wire crimps and switches.
The VFD's that I bought were fully encased in plastic were just over 100 quid

The man who knows all, Bob Minchin AKA 9fingers, wrote an extensive article on induction motors
and VFD's and it was through his efforts that I was able to delve into the world of three phase
Look it up


Happy to answer what I can

Tom

 

[Ttrees]

Here is a piccy of the switch, it may be clearer now
Here is the cheapest I could find...
http://www.ebay.co.uk/itm/1Pcs-Push-But ... 2749.l2649

Good luck

 

[Ozark]

Thanks very much Tom. I think it will take me a while to digest all this. I have read through Bob Minchin's guide also.

A question on terminology. Bob Minchin talks about an inverter and you talk about a VFD. After looking these up it seems you are talking about the exact same thing, which is more correctly referred to as a VFD. No need to spend time explaining what a VFD does (Google is my friend), I'm just trying to get things a little clearer in my head.

 

[Ttrees]

A question on terminology. Bob Minchin talks about an inverter and you talk about a VFD. After looking these up it seems you are talking about the exact same thing, which is more correctly referred to as a VFD.

The only difference is....
VFD's are £2:53 cheaper

 

[Myfordman]

It good to read that my guide is being helpful. As far as I can see the OP is on track for a good solution.

A couple of minor inputs.
1) I tend not to bother putting the inverter/VFD in a box but instead mount it on the wall well out of the line of fire of any sawdust. Air flow is usually from bottom to top so keep this free and a blow out with an airline now and then is just fine.

2) I buy a ready made stop/start button stations from Ebay
http://www.ebay.co.uk/itm/START-STOP-ST ... SwnipWaaQh
I have no commercial connection with Cropmaster other than as a very satisfied customer over many years.

HTH

Bob Minchin

 

[Ozark]

Thanks Bob.

Tom has practically convinced me to give this a go with his clear explanations.

Can I ask you Bob to comment on Option 2 in your guide where you use capacitors to generate a 240V 3 phase. That is without using the step up converter. It seems to not be preferred but I'm not sure why. Can you explain.

 

[Fitzroy]

Lose a chunk of power by creating a false phase with a capacitor, it'll start but max power down if I recall 30%ish.

F.

 

[Ozark]

So this is my planned setup. Would welcome any comments on it

I have no power to my shed yet so am wondering if I can run this off an extension lead. The sequence would be

20amp MCB in main house fuse board serving socket circuits. 230V supply
15m of extension cable (2 core + earth - can measure size later) with a 13amp fuse
2-3m of cable (2 core + earth) with a 13amp fuse
Connect to input of inverter
Stop/start buttons (NC / NO) connected to inverter
Output of inverter connected to motor with 3 core + earth
Motor set in in 220V Delta mode

For the inverter I have seen this one which is 2.2kw

http://www.ebay.co.uk/itm/De-Stock-2-2K ... Swu4BVsQKJ

De Stock 2.2KW 3HP 10A CNC 220V VARIABLE FREQUENCY DRIVE INVERTER VFD

 

[Ttrees]

I see those VFD's for 82.90 +14 postage.
Those are the vendors I went to last time, and I think I found one seller in UK.
It was delivered quick, It's probably the same folks.
If you do the research, I think HY group were claiming there were fake versions of their product,
And that was why some folks had bits missing ....(braking resistor components for dynamic braking) or
something else went wrong...
My drive had a tamper seal on the side which looked to be as legit as the rest.

You left out making the box for the VFD
Are you going to mount it to the wall. mine gets pretty dusty where it is positioned.

You probably want to have the saw in front of you to figure out what you want to do about switches.
And you probably want the saw in a good flat spot in your shed to figure where the placement to the VFD will be.

You want to get cable glands for the input and output of the VFD housing, and possibly for the switch housing if you
chose to make one, and doorbell wire for the switches, and crimp connectors that will fit motor terminals,
and smaller ones for your VFD
I used a thicker wires insulation to run them up through, was a PITA to do.

Some plastic for the VFD window will be sought after too.
Will send yo the parameters if you choose to go with Huanyang VFD
Good luck
Tom