Thread: Stepdown Transformers 240v to 110v for 2000w router motor

Brett

May I ask a silly question? If you already have a Triton router, why do you need a table such as you are describing? Why not look at a plate which can be used with the Triton?

Triton is about the only machine that can be used on a table and still allows above the table bit changing. About three years ago I was in the same position. I wanted to buy a Woodpeckers plate (without the lift as the Triton doesn't need it), but PWS were in dispute with them at the time and had temporarily gone to Incra. I ended up buying this:

Incra router plate 001.jpg

The top three inserts came with the plate and the others were an additional kit I purchased at the same time. I have still not built the cabinet to house this because I am desperately short of space until the new shed becomes a reality. Consequently I cannot speak for how it work either. As you can see the inserts are all still in their plastic bags.

The facility to use a winder to raise and lower the machine is better admittedly, but you pays your penny and makes your choice. I can't remember the cost, but it was around the $250 mark and that was bought in Oz, albeir three or four years ago. I think you are looking at three times that price for your set up.

I have needed to use the above so many times and even right now I have a large job making mouldings for which it would be perfect.

Regards
Paul

Originally Posted by Skew ChiDAMN!!

If I were you, I'd still go larger. After all you'll be driving a motor (regardless of size) so you should also allow for start-up current draw. I also couldn't see whether the 3000W rating is for continuous draw or merely peak.

See below. It sounds like its 2000W continuous and more than 3000W peak so it should be also able to handle the start up currents.
Remember what it's free running the 2000W router won't be pulling anywhere near 2000W
It's not like you run a router under load for more than a couple of minutes.

• Product Code: ST-3000
• Type: Autotransformer
• Input Voltage: 240V AC
• Input Frequency: 50Hz
• Input Fuse: 15A
• Output Voltage: 120V AC
• Output Frequency: 50Hz
• Continuous Output: 2000 Watts
• Maximum Output over 1 Hour Period: 3000 Watts
• Dimensions: 25 x 18 x 15.5 cms (LxWxH)
• Weight: 11.7 Kgs
• Input Cable Length: 54 cms
• Colour: Black

Originally Posted by BobL

See below. It sounds like its 2000W continuous and more than 3000W peak so it should be also able to handle the start up currents.
Remember what it's free running the 2000W router won't be pulling anywhere near 2000W
It's not like you run a router under load for more than a couple of minutes.

• Product Code: ST-3000
• Type: Autotransformer
• Input Voltage: 240V AC
• Input Frequency: 50Hz
• Input Fuse: 15A
• Output Voltage: 120V AC
• Output Frequency: 50Hz
• Continuous Output: 2000 Watts
• Maximum Output over 1 Hour Period: 3000 Watts
• Dimensions: 25 x 18 x 15.5 cms (LxWxH)
• Weight: 11.7 Kgs
• Input Cable Length: 54 cms
• Colour: Black

Heh heh. Mate if I was running a router for an hour, and it was pulling 2000w (or even close to it), I'd be a nervous bloody wreck at the end of it!

I do see Skew's point though - if ya gunna do it, do it properly for another $45, and have lot's of headroom. The bigger unit is about 4kgs heavier, and the dimensions are a bit bigger, but not too bad.

Paul, I am considering my answer.

Originally Posted by FenceFurniture

Heh heh. Mate if I was running a router for an hour, and it was pulling 2000w (or even close to it), I'd be a nervous bloody wreck at the end of it!

I do see Skew's point though - if ya gunna do it, do it properly for another $45, and have lot's of headroom. The bigger unit is about 4kgs heavier, and the dimensions are a bit bigger, but not too bad.

Don't forget that "Headroom" is ultimately limited by what mains circuits you can plug into.
The bigger unit will utilise its capability on a 15A+ circuit but not a 10A circuit.
If the bigger unit is used on a 10A circuit, the 10A circuit breaker will trip before the internal breaker on the bigger unit.

In the original link to the transformer, at the bottom below the data section, they have a Q&A type section, including running motors off the transformer. They reccommend uprating by a factor of 4-6 times for motor starting. This would be fairly common for induction motors etc.

Does the router motor you are considering have soft start? One of the great features of soft start is that the start currents are limited becase the supply voltage to the motor is ramped up over a couple of seconds. With a soft start motor, you could probably use that transformer for motors up to its 2000W rating safely, if you want more grunt at the motor you are probably looking to the next largest transformer. Remember also that in a router situation, you may be making a multitude of starts in a fairly short period, and the thermal effects of starting a hard starting motor will be cumulative.

They claim a 3000W peak rating for 1hr, but I would be suspicious of that for regular use. Regardlesss of load, the transformer core should be able to reach a stable temperature for the load applied within five minutes of use at that load. If a 3000W load takes it to a safe stable temperature within 5 minutes, it should be able to maintain that temperature and be safe on a continuous basis. A 1 hr rating seems very long for a peak load rating.

The transformer is identified as an autotransformer, which means that it has a single winding with 240V applied accross it, and it is tapped at the midpoint to take off 120v for the load. Any wiring errors in the unit itself, or the supply wiring, extension cords, outlets etc supplying the unit can mean that a load connected can be supplied from 240V with the return line floating at 120V, (motor sees the difference of 120V). In theory, the motor insulation should be able to withstand this voltage, but getting a supplier to document it as safe would be difficult, as it is generally assumed that one side of the connections would be at 0V.

I would also be having the supplier confirm the current rating of the outlets on the unit. It has two outlets, which should be wired in parallel for an autotransformer, but it quite likely that individual outlets will be rated for somewhat less than the full capacity of the transformer, and overloaded when asked to supply the rated output via a single outlet.

Originally Posted by malb

. . . .Does the router motor you are considering have soft start? One of the great features of soft start is that the start currents are limited becase the supply voltage to the motor is ramped up over a couple of seconds. With a soft start motor, you could probably use that transformer for motors up to its 2000W rating safely, if you want more grunt at the motor you are probably looking to the next largest transformer. Remember also that in a router situation, you may be making a multitude of starts in a fairly short period, and the thermal effects of starting a hard starting motor will be cumulative.

I recently tested out what sort of start up currents my Triton router (3HP with soft start) required.
On slow speed the max start up current visible on a DMM was 5.7 A, on highest speed it was 7.5 A
Free running current on highest speed is 2.5A - time to reach free running current on startup was about 3 seconds
Interestingly once warned up the subsequent start up currents were a little less.

Compare this with start up currents of 35A on a 2HP DC, and 57A on a 3HP DC - DCs are of course loaded up with air to move right from the start.
The 2HP DC was supplied with a 10A plug and runs happily for hours on a 10A circuit.

Just to put a spanner in the works, do the Australian Wiring regs allow an auto transformer? I can't remember and am too lazy to look it up. I know they prohibit the high resistance leads that are used in some places to run 110/120V radios and lead lights etc on 220/240V mains.
Regards

Originally Posted by BobL

Don't forget that "Headroom" is ultimately limited by what mains circuits you can plug into.
The bigger unit will utilise its capability on a 15A+ circuit but not a 10A circuit.
If the bigger unit is used on a 10A circuit, the 10A circuit breaker will trip before the internal breaker on the bigger unit.

Yep, got me a couple of 20A courtesy of NCArcher.

Malb, I sent an email to the supplier this morning querying the manufacture (used to be part Aussie, now fully......have a guess), and he raised the same point about accumulated heat. Don't know about soft starts yet - maybe some have it. As for get confirmation of currents etc - mate it's made in China - they'll put anything you want on it, and for no extra cost to boot!

Paul, I'm still working on your answer.

Originally Posted by FenceFurniture

Paul, I'm still working on your answer.

Regards
Paul

Originally Posted by FenceFurniture

Don't know about soft starts yet - maybe some have it.

Brett

My interpretation is that the soft start refers to the machine and in the case of the Triton router it does indeed have a soft start. BobL's earlier post identifies the huge difference this can make to a starting current. It is another advantage of a VFD, if you decide to travel that path, in that the unit can be programmed for a soft start to limit the in-rush current on startup.

Regards
Paul

Originally Posted by FenceFurniture

Yep, got me a couple of 20A courtesy of NCArcher.

Well, 'Shmiller posed such a difficult bloody question that the answer required a new thread.
https://www.woodworkforums.com/showth...2173&p=1749549

Hmmmm.... the plot thickens.....

This Suhner jobbie is made in Switzerland and that makes it attractive



The dealer is on deck now, and so I've been having some dialogue. The casing is plastic, so it obviously can't get too hot. It only takes a maximum 12mm collet (bugger, I've got a enough ½" shanks to make that a pain), but there is a ¼" collet available.

He doesn't think it's a good idea to hold it by the casing, but I have an idea. Starting with a metal cylinder that has a solid base (think of a cylindrical bucket):

• put a 43mm hole in the centre of the base, and some way of securing the collar in there
• cut the cylinder length down to sit in those "brass" jaws of the router lift at the right height
• put enough slots in the wall of the cylinder to allow for the cooling of the plastic case

The question is: what is the maximum cylinder that those jaws can hold? Will email JessEm, and get a response after midnight, but in the meantime, what do you think of this idea?

Originally Posted by FenceFurniture

It's probably about time to get an update on Stepdown transformers.

It seems highly likely that I will need to buy a router motor-only to fit to a router lift (I know some lifts will take normal routers, but not the one I'm thinking of - motors only). There are no motors-only of decent power available in Australia, which means either a 110-120V jobbie from the USA (which are the routers that all the lifts are made for) or perhaps something from Europe (certainly solves the electrickery problem, but the lift makers can't guarantee that they will fit the lifts properly).

And so it goes on. It seems that the best solution will be a 110v motor, for which I would then need a Stepdown Transformer, covering adequate power. The biggest motor on the USA market is 3¼HP, so say 2500 watts. This transformer should cover it, according to the website. For a smaller motor I may be able to drop down to the ST 2000, BUT it's probably a good idea to have ample power coverage - just in case another 110v tool lands in my shop.

So, my question to the elec-heads is: am I on the right track with a transformer like that? What should I be looking out for? Is there a better solution?

I must say that a European built motor is appealing because of the quality - the USA ones are probably all Mexican or Chinese (certainly Porter Cable is now Mexican, and the quality is apparently down from some that I have read). Euro would also obviate the need for a transformer, so the cost increase for good quality is also negated.

Be very carefull, the use of this type of transformer (autotransformer) is expressly prohibited by Australian SAA Wiring Rules AS3000. To quote: "4.28.4.2 Prohibited use. Autotransformers shall not be used for reducing or controlling the voltage to equipment which is likely to be handled in normal use." For safety reasons you will need an Isolation Step-down transformer, which will be very expensive.

Chas.