Hello Guest it is June 17, 2019, 07:58:32 PM

Author Topic: CS Labs CSMIO/P-A  (Read 15133 times)

0 Members and 1 Guest are viewing this topic.

Re: CS Labs CSMIO/P-A
« Reply #150 on: August 04, 2018, 05:11:26 PM »
Hi Mick,
your musing about a 5kW single phase to three phase converter:

I have attached I pic of the specs for a Allen Bradley 2098-DSD-030 which is the largest single phase servo drive that I know of.

Note the continuous output current is 15A. Note that this is the peak amplitude, ie 15A peak or 10.A rms.
Note the continuous input current is 28A and the inrush and overload current is 50A.

This drive will handle about 2.2 kW or there about.

If you want to drive a 5.5kW servo then then input current would be something like 70A and the inrush/overload current 125A.
That's just plain physics......your domestic supply would never handle that.
Servos are very 'power dense' so the situation would be even worse for an asynchronous motor, by about 25%.

The last item I highlighted in the pic is the DC Link capacitors.  The incoming AC supply is rectified and smoothed by the DC Link capacitors.
They supply the drive in between the charge cycles of the incoming rectified supply. If they are not large enough the DC Link voltage will
sag between the 50Hz peaks. If you wanted to improve the performance of a single to three phase converter this capacitance would have to
increase markedly.
A three phase drive receives rectified supply charge cycles three times more regularly and can have therefore a third the capacitance as its single
phase brother and achieve the same result.
The upshot is that you COULD run a 5.5kW motor from a single phase supply IF you are prepared to have the power supply company uprate your
connection AND you were prepared to build what amounts to a HUGE 320VDC power supply. All possible but not really practical.

Craig
My wife left with my best friend...
     and I miss him!
Re: CS Labs CSMIO/P-A
« Reply #151 on: August 04, 2018, 05:17:42 PM »
Hi Hood,

Quote
you have to register with Rockwell to get it but registration is free and painless
I tried that but without supplying a purchase number they wouldn't accept my registration.


To Mick,
sorry forgot to attach the pic that relates to my previous post.

Craig

My wife left with my best friend...
     and I miss him!

Offline Hood

*
  •  25,844 25,844
  • Carnoustie, Scotland
    • View Profile
Re: CS Labs CSMIO/P-A
« Reply #152 on: August 04, 2018, 05:48:08 PM »
I use the DSD-030 drive with  H and F 4075  motors, I am sure they are around the 3Kw size.
Re: CS Labs CSMIO/P-A
« Reply #153 on: August 04, 2018, 05:54:49 PM »
Hi Hood,

Quote
I use the DSD-030 drive with  H and F 4075  motors, I am sure they are around the 3Kw size

I'm sure you are right....the unit I was supplied is a DSD-020 and it does a pretty fair job of powering a 1.8kW servo. The truth is you
have to really push things to get it anywhere near its maximum and the amount of electrical energy circulating when you do is scary!

Craig
My wife left with my best friend...
     and I miss him!

Offline Hood

*
  •  25,844 25,844
  • Carnoustie, Scotland
    • View Profile
Re: CS Labs CSMIO/P-A
« Reply #154 on: August 04, 2018, 05:58:35 PM »
Specs of the motors on a DDM drive which is the older version of the DSD.
H series Low inertia I make a bit over 3Kw, the High Inertia F motors just under.

Offline Hood

*
  •  25,844 25,844
  • Carnoustie, Scotland
    • View Profile
Re: CS Labs CSMIO/P-A
« Reply #155 on: August 04, 2018, 05:59:59 PM »
The F series would make a nice spindle motor on a smallish lathe.
Re: CS Labs CSMIO/P-A
« Reply #156 on: August 04, 2018, 06:26:18 PM »
Hi Mick,
I thought to follow up on the discussion about LARGE single to three phase converters. Basically your power company would be
within theirs rights to say 'No, we will not permit you connect such a device to our network'.

The first pic is a representative circuit of an off-line input rectifier you might expect in a single phase VFD or servo drive.

The second pic show the currents and voltage when powered by a 230Vrms 50Hz supply. Note the output voltage (green trace), approx. 320Vpeak
but notice it sag between cycles. You would have to say that the DC Link capacitance is marginal for the output current.
Note the output current (red trace) is reasonably steady at about 12A but look at the supply input current (blue trace). It has peaks of about 180A!

This is a real problem....offline rectifiers draw current in high amplitude pulses with big gaps in between. The power companies hate that, they call it power factor
but in truth its more about current distortion. Any other customer hooked to the network is going to have their input supply degraded because of your device.
There are various means, both passive filters and active powerfactor correction circuitry that will solve this problem but they are expensive.

Given the plethora of electronic devices that have such simple input rectifiers and in ever increasing numbers, power companies are now having to insist on
powerfactor correction and prosecute you if you fail to comply. They have to try to protect their network for all our sakes.

Given the size of the inverter you would require for a 5kW motor I think you would come up in the power companies radar and they would ask some very pointed
questions and probably insist that you improve your installation. Industrial users are familiar with this problem and are required to spend somewhere between a quarter
and a half of their total cost of installation on the required powerfactor correction equipment.

Hood has pointed out that a 2098-DSD-030 can mange about 3kW, which is pretty damn fair. Given the exemplary torque characteristics of servos verses ansynchronous
motors I think you'd find this a very suitable replacement. Certainly it represents a practical limit to singe phase technology. DSD-030's are not nearly as common or as
cheap as the smaller 020's, but can be had for around $400US on EBay.

Craig
My wife left with my best friend...
     and I miss him!

Offline Hood

*
  •  25,844 25,844
  • Carnoustie, Scotland
    • View Profile
Re: CS Labs CSMIO/P-A
« Reply #157 on: August 04, 2018, 06:37:52 PM »
One word of warning if thinking of going down the Allen Bradley DSD drive route for a spindle.
You have to be aware that these drives come in two main series, standard DSD-*** drives and High Voltage (ie 3 phase) they have a HV designation in the name so for example you get the low voltage (230V ) drive DSD-030 and the High voltage is DSD-HV030. Make sure you don't get the latter :)
Re: CS Labs CSMIO/P-A
« Reply #158 on: August 04, 2018, 06:48:58 PM »
Hi,

I found a cheapie:

https://www.ebay.com/itm/Allen-Bradley-2098-DSD-030-Ser-B-Ultra-3000-Servo-Drive/123195136805?hash=item1caf009b25%3Ag%3AzmoAAOSwKX9apbWe&_sacat=0&_nkw=2098-dsd-030&_from=R40&rt=nc&_trksid=p2060353.m570.l1313.TR1.TRC0.A0.H0.X2098-dsd-030.TRS0

They range from as low as this up to about $2000 for new (old stock).

Another matter to be aware of with these drives (all the DSD-0X0's) is that they don't have a built in switch for a braking resistor.
There is a separate device that hooks to the DSD-0x0 terminals which when the DCLink voltage spikes due too deceleration switches in the braking resistor within it.
The devices come under great stress and blow up easily. They are not especially complicated, I'd make my own...electronics is my thing and I work in
the industry where I wouldn't even have to buy the components....they come over my bench as surplus all the time.

Craig
My wife left with my best friend...
     and I miss him!

Offline Hood

*
  •  25,844 25,844
  • Carnoustie, Scotland
    • View Profile
Re: CS Labs CSMIO/P-A
« Reply #159 on: August 04, 2018, 06:55:22 PM »


The 030's and 075's  do, the smaller ones, as you  don't although in most cases it is not required.
BTW the DSD-075's are 3 phase 230v, the old DDM-075's could be used 230v single phase but were basically derated to 030's.