Some of the "Driveswarehouse" type places sell solid state "phase
converters" that have no speed control, but they seem to cost as much or
more than the equivalent sized VFD. No idea why. It must be driven
by the marketplace.
I suppose if all you are driving is a blower or pump then having onboard
braking circuitry might be close to worthless.
The Estop requirements on most automation machinery requires a rapid
stop on all rotating machinery.
So... is anyone going to buy the $125 5 hp drive and let us know how
long it lasts before the drive goes "pop". ;-)
Dave
On 1/2/2018 6:35 PM, Gregg Eshelman via Emc-users wrote:
I run the VFD (that's never varied) on my old Monarch lathe without using
braking. It has terminals to connect a braking resistor but for this machine
there's no need.
What I find crazy is that a simple, single function device that only converts single phase to three phase, without all the fancy features of a VFD, costs so much more than a VFD. When a 3HP VFD for 220~240VAC input can be had for under $300, why isn't a version that does absolutely nothing, no adjustments, no variation, no programmability, but do the phase conversion not cost well under $200 instead of a whole lot more?
If some company produced a box that was just a phase converter with an on/off
button and terminals for a remote switch as the only 'extras', and put a
$199.99 price on it, they'd be hard pressed to keep up with demand.
On Tuesday, January 2, 2018, 9:33:50 AM MST, Dave Cole
<linuxcncro...@gmail.com> wrote:
So what exactly do they do when the bus voltage rises during decel ??
Or is there no decel control at all?
I've never seen a drive without braking circuitry and DC bus voltage
control.
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