It's not the capacitor on phase A. Oh pooh. Now I have to look
for zebras rather than horses...
Yes, I am aware of the basic motor physics ;) That "about a
second" is with a stiff supply. Mine is apparently not stiff
enough <that's what she said> :D
My original plan was to acquire a 618T with the 400 Hz
three-phase supply - usually much cheaper than the 28 vdc or the
400 Hz single phase versions. But this inverter is becoming a real
white elephant. It would be running all the time, not PTT like the
ART-13.
Anyway I am tempted to go buy a pair of car batteries and find
out, just because I'm stubborn that way! (My two "ARC-5" receivers
have their dynamotors, but I only run one at a time, and the 28v
supply I built with a handy Stancor RT-204 transformer has no
trouble).
Charles, WB3JOK/0 since '76
On 2/26/22 15:13, Christopher Bowne
wrote:
No, just a an Ames (Harbor Freight) 80 buck multimeter with a
clamp on AC or DC ammeter.
Peak current is always at initial 0 RPM, as the motor winds
up the counter EMF brings the current down in about a second.
Basic
DC motor physics. Considering the instrument pedigree I take
no responsibility for the accuracy of the reported result.
As an alternative to floating batteries on the output of a DC
supply, one could implement a step starter circuit, but you
would need
some hefty dropping resistors and contactor relays. Wouldn’t
lend itself to quick PTT operation on voice.
Chris AJ1G
Stonington CT
Sent from my iPhone
Thanks, there's a data point of
5 times the nameplate.. What was the decay time of
that 160 amp peak (did you use a scope)?
If I HAD a couple of spare car batteries I'd
certainly try them ;) but have you seen the prices
lately? they start at $55 plus core plus tax at
Wally World...
On 2/26/22 13:37, Christopher Bowne wrote:
I’ve measured the peak
inrush current on my ART-13’s DY-17A dynamotor,
it was a nominal 160 amps. Just float a couple
of 12 batteries across the output of your
supply, make sure that they are fully charged
and full sized automotive or deep cycle marine
type, small one may not deliver enough peak
current to preclude tripping the output breaker
in on your high current supply.
Chris AJ1G
Stonington CT
Sent from my iPhone
On Feb 26, 2022, at
13:57, Charles via ARC5
<arc5@mailman.qth.net> wrote:
I am sure I would
have no trouble starting a DY-17 with a 33 amp
full load rating. This beast is 3.5 times that
full load draw and consequently any surge
current would likely also be 3.5 times that...
Anyway I am going to
investigate shorts on the AC side, and my
prime suspect is the (noise reduction?)
capacitor on A phase. Hope it's not the
armature. It does have a repair request tag
from the 80's or 90's (don't remember at
moment) and an unreadable "Serviceable" tag.
The electromechanical regulator (carbon
piles!) will get a look after I check the cap.
Something else I have no experience with.
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