[Larken]

Volts x Current x %eff x PF
--------------------
746

Efficiency is between .75 and .90
In a single phase motor the PF (power factor ) is 0.91

The three-phase motor is 73% more powerful than an equivalent motor using single phase. The number 1.73 is added to the wattage side of the calculation to reflect this increase for 3 phases.

http://www.bacharach-training.com/norm/electric.htm


A single Phase motor is like a single cylinder engine , compared to a 3 cylinder which has 3 times the power pulses per turn.

Larry, I will check the nameplate on the Colombo. It has 220 and 380 volt specs

Larry K

[Allyd1964]

Hey all, I have not posted here for sometime but I thought I might add to this topic.

I purchased one these Chinese 2.2kw motors and drive approx 9 months ago. I fitted the water cooling to it using PC water-cooling components. All was working very well until approx 2 months ago when the drive unit stopped, it turned out to be a dry solder joint. Not big problem but annoying all the same. Unfortunately last week a small water leak developed that I did not notice until the breaker tripped. Scared the crap out of me, ruined the job I was doing and generally stopped me dead in my tracks. The water had leaked onto the top of the motor and after several attempts of drying the motor out I have official given up. As I am a hobbyist the cost of these units is positioned perfectly, yes you get what you pay for but I can't justify a $5000 outlay in one hit.

Today I pulled the motor apart to see what makes it tick, yes the bearings are "Made in Germany", there are 2 7005 bearing stacked with a single 7002 bearing at the other end. The bearing fit into the case and onto the shaft is on the loose side for my liking, maybe the heat at running temp tightens things up. The water galleries are very small which is why you need a decent pump, I have not been able to get the front end cap off yet to see exactly where they go.

Today I bought myself another 2.2 kw motor and drive exactly the same for $513 USD delivered, but this time I know what I getting and I understand what I have payed for.

[Larken]

but I can't justify a $5000 outlay in one hit.

$5000 ??

So far you've spent enough to get a 3Hp Colombo , Elte or Tecknomotor from Italy. Also a 2Hp Perske is cheaper than the price of 2 china spindles.

http://www.larkencnc.com/spindles.htm

Check these out. And they actually come mounted in a frame with a proper connector box, not wires hanging out

[Allyd1964]

The other main reason for going with the Chinese spindle and drive option was the noise factor, my machine is in a suburban backyard shed which I have tried to sound proof with some success. These spindles run very quite.

However, IF I was setup in an industrial area and my "hobby" turned into something more serious then would definitely go with a higher quality spindle and drive. Also keep in mind that the total cost so far has been under $1100usd. But thanks for the link, you have some nice products there.

[rowbare]

Today I pulled the motor apart to see what makes it tick, yes the bearings are "Made in Germany", there are 2 7005 bearing stacked with a single 7002 bearing at the other end. The bearing fit into the case and onto the shaft is on the loose side for my liking, maybe the heat at running temp tightens things up. The water galleries are very small which is why you need a decent pump, I have not been able to get the front end cap off yet to see exactly where they go.

Could you post some pictures of the disassembled spindles with perhaps a few words on how you got it apart? Someone recently posted that the bearings had gone on the spindle he bought and was wondering if they could be replaced. I am sure that your experience would be most valuable.

bob

[Allyd1964]

Could you post some pictures of the disassembled spindles with perhaps a few words on how you got it apart? Someone recently posted that the bearings had gone on the spindle he bought and was wondering if they could be replaced. I am sure that your experience would be most valuable.

bob

Hi Bob, First step is to remove the end cap which houses the plug, if you plan to rebuild the unit then desoldering the connections is the way to go, carefully marking the wires for later. Next, remove the plastic cap, this exposes the small bearing that sits within a large steel casing. Next remove the front lock nut, the hardest part of dismantling the spindle was getting this lock nut off. I suspect they may have used some loctite or similar on the thread. The next step is removing the shaft but you must bear in mind that my dismantling method was not the most gentle, in fact I used blunt force trauma on that poor spindle. The shaft and end casing is removed together. The end casing is pressed into the body, to minimize damage to the small bearing I suggest using a press to remove it. I have no idea how they fitted the small bearing onto the shaft, I have no access to a hydraulic press.

Hope this helps.

Cheers

[stoughto]

Larken,

I have a 1/2 hp trim router on my machine now, and wonder whether I need to upgrade. I built a Solsylva dual leadscrew table from his plans:
http://solsylva.com/cnc/original_cnc_plans.shtml

On the page you reference
http://www.larkencnc.com/spindles.htm
you have 2 hp Perske precision high frequency spindle and
2Hp Bosch Variable speed router listed. They are both 2 HP,
and have the same range of RPMs.

How would I decide between these two?

1. Is there a significant cost difference?
2. Does one make more noise than the other?
3. What kind of cuts will the precision of the spindle do better than the router?
4. Am I limited by the precision of the machine? It uses conduit, inline skate bearings, threaded rod, and connectors.
5. What else should I ask?

Thanks.

[ger21]

1. Is there a significant cost difference?

Yes, the Perske is at least 4-5 tmes more money than a Bosch router.

2. Does one make more noise than the other?

Yep, the Bosh is much louder at higher rpm's, and a bit louder at lower rpm's too.

3. What kind of cuts will the precision of the spindle do better than the router?

You can buy precision collets for the router at www.precisebits.com Then the only difference would be that the Perske has much more power than the Bosch.

4. Am I limited by the precision of the machine? It uses conduit, inline skate bearings, threaded rod, and connectors.

Yes.

5. What else should I ask?

If you don't mind the louder noise, and if it has enough power for your needs, the Bosch is a much more cost effective solution. You can replace brushes and bearings for around $20 or so, so you can get a very long life from it. Replacing bearings in the spindle can be a several hundred dollar repair, when they fail. Also, the Bosch can accept 1/2" shank bits, which are very common, while the Perske is limited to 3/8".

[stoughto]

Using a precision collet in the Bosch will make it work as precisely as the Perske? Isn't there an issue with how good the bearings are on the two, or is that tolerence equivalent?

Both the Perske and the Bosch are described as 2 HP, yet you say that the Perske is more powerful. How can that be?

So, if I can put up with the noise and don't need the power, then it is better to spend money on other parts of the machine with the money I save by purchasing the Bosch instead of the Perske.

[rowbare]

Both the Perske and the Bosch are described as 2 HP, yet you say that the Perske is more powerful. How can that be?

The horsepower ratings on the Bosch come from the marketing department, the ratings on the Perske come from the engineering department.

The Perske can put out its 2 HP all day long, day in day out. The Bosch can put out 2 HP peaks for brief periods. I am not knocking the Bosch. It is a fine machine but in the end it is a hand held router. In its intended use it runs for periods of a minute or so at a time and only needs to hit its peak power rating for short periods before it gets shut off and gets a chance to cool. That they work as well as they do on cnc routers is a testament to how well built they are. But they don't really compare to a purpose-built spindle.

However some people do use regular routers for production work. There was one fellow who posted that he had bought several of them and a box of bearings. He would run the router till the bearings got noisy then he would swap it out for another. When he had time or he put in the last router, he would replace the bearings and put them back into the rotation.

bob

[Larken]

On the page you reference
http://www.larkencnc.com/spindles.htm
you have 2 hp Perske precision high frequency spindle and
2Hp Bosch Variable speed router listed. They are both 2 HP,
and have the same range of RPMs.

How would I decide between these two?

1. Is there a significant cost difference?
2. Does one make more noise than the other?
3. What kind of cuts will the precision of the spindle do better than the router?
4. Am I limited by the precision of the machine? It uses conduit, inline skate bearings, threaded rod, and connectors.
5. What else should I ask?

I have 2Hp perske ER16 collet($995) and 2Kw TecknoMotor ER20 collet($1095)
These routers only make some fan noise, more like a turbine sound, not a roar like a Bosch or Portercable.
3. What kind of cuts will the precision of the spindle do better than the router?
A Bosch collet cannot hold a cutter straight within 1-2 thou so they only cut on one side of the cutter usually.
These spindle produce a better cut with less vibaration. They are accurate enough to hold a 6" long cutter. Try that with a Bosch.

4. Am I limited by the precision of the machine? It uses conduit, inline skate bearings, threaded rod, and connectors.
Its kind of like putting a porsche motor in a homemade dune buggy, but its up to you.

BTW, Im sure if perske and others just sold the bare motor without a mounting body, Fan and let the wires dangle (like a chinese spindle), they would cost just a bit more than a chinese spindle.

A good inverter for these spindles is a Hitachi , you can get these for just over $200 from drives warehouse.

You can buy precision collets for the router at www.precisebits.com Then the only difference would be that the Perske has much more power than the Bosch.

A bosch can't hold a ER shaft extender anywhere near as accurate as a Euro spindle. The power is about the same, one difference is the bosch dies down when under load, the perske holds its full rpm.

[ger21]

A bosch can't hold a ER shaft extender anywhere near as accurate as a Euro spindle.

If you'd looked at the link, you'd see that I linked to a replacement collet with runout <= .0004", not a collet extension. These collets can give you the same quality cuts as an expensive spindle. They just can't give you more power.

And you might want to update your website. The 2007 price list shows the 2HP Perske as a $2300 upgrade.

[Larken]

If you'd looked at the link, you'd see that I linked to a replacement collet with runout <= .0004", not a collet extension. These collets can give you the same quality cuts as an expensive spindle. They just can't give you more power.

I thought you were saying with this ER extender mounted on the Bosch router, the accuracy would be as good as a Perske.

And you might want to update your website. The 2007 price list shows the 2HP Perske as a $2300 upgrade.

Thats with a ACtech inverter, installed with 3phase wire and mounted on our cnc router, programmed, tested and warranteed . The ACtech MC1000 is a more expensive inverter with a stand alone metal case (not plastic).