Only 1500rpm though.

Craig

Please images of my phase converter temporarily attached to my lathe.

Here is a link to a 15hp one on ebay. Very popular over here.

https://www.ebay.co.uk/itm/Digi-phase-Converter-1-3-Phase/183353569642?hash=item2ab0b9716a:g:bYAAAOSwhilbYKsy


Cheers
Mick

Strange it says that in the Manual but the torque graph shows 19nm up to around 2600rpm then drops to 9nm at 3000rpm???

Cheers

Strange indeed.

The BCH2MR3023CA6C shows 14NM straight through to 3000rpm. Would this be a better option?

Cheers

Hi,

Strange it says that in the Manual but the torque graph shows 19nm up to around 2600rpm then drops to 9nm at 3000rpm

Its called 'field weakening', a clever technique for extending the rev range of a motor which would otherwise top
out a a lower speed due to lack of voltage. This is a pretty radical reduction though.

Craig

Hi,

the first motor:

power =2600 X 2 X PI / 60 X 19
          =5172 W

the second:
power = 3000 X 2 X PI / 60 X 14
          =4397 W

So despite the first motor dying at speed, in the field weakened operating condition, it is still the more powerful motor.

Hey, all these high power motors are wonderful things but you have to squeeze the electricity to run them
through your domestic supply. Not withstanding what looks to be a really impressive single to three phase converter
you will still have to supply it something like 60A to produce 5kW output. Will your domestic supply and cabling
accommodate such high currents?

Craig

Hi Craig


Thanks for the info. We have a 100amp single phase supply. If I remember right I had to put a 50 or 60amp B rated breaker in. For the initial surge.
I believe the motor in the converter is bigger than 5.5kw.

Cheers

I need to speak to SMP as there website is no longer showing these converters. Don't want to spend the money on the 3 phase spindle then have a problem with the converter and not be able to get it repaired.
Cheers

Hi Mick,
kool, it sounds then that you have taken some precautions against overloading your supply.

Just a few thumbnail calculations:

current (assuming unity power factor) =5000 (W)/ 230 (V)
                                                       =21.7A rms

21A doesn't sound too bad does it? But remember this embodys the assumption that unity power factor, ie perfect power factor applies.
We all know that there is never a perfect power factor. I would be prepared to guess that the converter you have is good, even very good, it
would certainly account for their popularity. Lets assume that your converter has a power factor of 0.95, most industrial electricians would regard
that as very good indeed.

current (assuming 0.95 power factor) =21.7 / 0.95
                                                      =22.9A

Still pretty fair, only 23% of the current available from your 100A domestic supply.
The real trouble now comes when three phases generated by your converter are applied to your servo drive. You recall the circuit diagram that I posted
earlier, the three phase version is very similar and suffers the identical power factor problem.

I repair welders for a living, inverter welders particularly. Day after day I see for instance a single phase stick welder producing 100A at 20V into
our load bank and yet 20A indicated current coming from the single phase supply. We'll do the energy balance to determine the effective power factor of this
situation:

input power (indicated)= 230 (V) X 20 (A)
                                 =4600 W
output power( actual)= 20 (V) X 100 (A)
                               =2000 W

Power Factor (effective)= 2000 / 4600
                                  =0.438

Just about all single and three phase off-line rectifiers suffer this power factor degradation. There are circuits to correct it, I suspect your converter uses them
but your proposed servo drives do not.

Thus lets now calculate the current required by your servo drive referred back to the single phase supply assuming this power factor:

current (single phase equiv)= 5000 (W) / 230 (V) / 0.438 (power factor effective) / 0.95 (power factor converter)
                                        =52.24A rms

Lets put that number into perspective. Firstly its one half of the rated supply of your domestic network connection. Secondly it near the circuit breaker
rating and this is just rated current, not any overload or inrush current.

You can see now that the power factor, which is far from an easy measurement, affects so dramatically the required input current. I've seen power factors
as low as 0.3 but 0.4 to 0.5 are the norm for reasonably made off-line rectifiers of simple type. You can also see my concern that you might cause your electrical
installation harm or risk fire or injury unless you understand the demands of your servo drive.

Craig