Re: Bridgeport boss 4 Spindle not powering up (continued)
- From: "rigger" <dgrup@xxxxxxx>
- Date: 14 Feb 2006 20:22:57 -0800
DoN. Nichols wrote:
According to jak <jakdog@xxxxxxxxx>:
Thanks for the helpful suggestions regarding my Boss 4 spindle not
powering up problem. Here is some more information:
The Spindel does easily Rotate
The Belt is fine
The problem is not low spindle oil
O.K. Though low spindle oil would simply make it noisy, not
keep it from turning.
I went through the Bridgeport troubleshooting process and checked the
following: Power after main fuses, power after Transformer 1, power
after transformer 2, 24 VDC. DC power output at bridge rectifier, 56
VDC supply, All the regulated and unregulater logic power supply
voltages.
Potential issues:
The rear Fan does not operate
Easy enough to replace.
the spindle overload (1MOL) kicks out every once in awhile and needs to
be reset. (1 MOL picture in metalworking dropbox boss_4_to_motor just
bnarely out of picture in upper left)
Hmm ... in that photo, I see the interlocked pair of contactors
(on the left) which select for forward or reverse operation, and the
heaters (bottom right) which sense excess current through the motor and
disable the contactors so there can be no power to the motor.
Is it possible that one of the axes is hitting a limit switch?
If so, the interlocks may prevent powering up the motor.
When spindle is turned on, voltages going to the spindle motor is not
240V, between T1 and t2 it is 220V, betwenn t2 and t3 it is 240V and
between T1 and t3 it is 160V.
Hmm ... a bit low. Is this from a rotary converter? I think
that it perhaps needs to be tuned with capacitors for a better balance.
When spindle is turned on, power after the 3 main fuses is also low,
same values as above.
What are the voltages with the spindle turned off? That poor
balance will perhaps make it more difficult to start the motor, and will
certainly introduce problems for the axis stepper drivers. And -- if
the one phase gets *too* high, you are even likely to blow the
transistors on one of the three axes.
If the three phase is coming from the power company, and is that
far out of balance, you have serious problems. (Or perhaps some
terminal screws between the three phase power source and the input to
the back are loose.
I presume that you've checked all three of the big cartridge
fuses in the upper right of the "boss4back.JPG" image. The ones which
look lie black sticks of dynamite. :-) I see that at least one has been
replaced, since it has a different color of label than the other two.
So If the heaters are where I think they are, (3 orange cylinders in
metal working drop box, boss4_back) then there are actually 6 wires
coming out of it, not 3. I tried disconecting all 6 and doing as
instructed, with no effect.
No! What that looks like is the big three-phase transformer,
which provides the power for the three stepper motor drives for the
three axes.
The heaters are actually quite small. They are not to heat the
box of electronics, they are to heat devices which sense (by the heat)
overcurrent in the power to the three-phase spindle motor. They are
part of the small black object in the "boss4_to_motor.JPG" image at the
bottom right. I think that they are the three objects on the top (that
is, the surface towards you as photographed). You remove them with the
two screws each, to change them for different current ratings if you
re-wire the motor (and all of the transformers in the system) for 440
VAC operation instead of 220 VAC. Below them are the things which they
heat and which release to interrupt the circuit.
Anyway, that box is where I plan to install my VFD to drive the
motor, and all of the rest will run from 240V single phase. (But it
won't, and *can't* be the original BOSS-3 or BOSS-4 electronics. --
*That* needs the full three phase, and well balanced, to drive those big
stepper motors from power derived from the big three-phase transformer.
Servo motors and separate servo amps will draw a lot less power than
this does.
When this happens, you will have to get into the box on the side
and reset whichever of the three has tripped, as you can't get power to
the motor until that has been replaced.
Below the big orange three-phase transformer are three saturable
reactors (two side by side in the bottom, and one above them sort of
towards the center), which are used to reduce the voltage fed to the
stepper motor drivers when the steppers are stopped, or moving slowly,
to keep from burning out the windings in the stepper motors. They need
a lot more voltage when being stepped fast, and the saturable reactors
allow switching between the higher voltage and the lower voltage.
Note that I think that I see a diagram printed on the inside of
the back door which should identify the various objects in there.
I believe that the objets shown in the "boss_4_to_motor.JPG"
image are in a second box attached to the right (as viewed from the
back) of the main electrical box on the back.
Another problem with an instruction I got in the manual "Check all
contacts to the logic boards and terminal strips" Does that mean check
for continuity across all terminals?
Probably looking for loose connections. Power it off,
disconnect from the power entirely, and tighten the screws on all of the
terminal strips, and those which are awkward to reach (such as the
contactors in the "boss4_to_motor.JPG" image, at least try wiggling
them. If any of those move, you'll need to pull the contactor out to
where you can tighten those terminals.
So I hope this is enough info for some saint out there to help me out,
I really don't want to call inthe $100 tech.
We're *trying*. But it is rather difficult to do a good job of
troubleshooting something this complex at a distance, when you are
having difficult identifying the various parts about which we are
asking.
Note that this also depends on the proper relays being in the
sockets in the base of the computer chassis on the right side of the
machine (as viewed from the front). And -- if a safety fix has been
installed, you need to reset a safety interlock on the motor switch pod
to confirm that you have changed the tool and have your hands safely
clear again -- *each* time the system thinks that a tool needs changing,
which probably includes when it boots up.
Have you ever seen this operate? If not, you may not know how
to reset the CPU on initial power on.
Good Luck,
DoN.
--
Email: <dnichols@xxxxxxxxxxx> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
Good ideas DoN. I was hoping someone with more specific information
would show up to help jak. I can work my way through the average power
circuits but there's sure nothing like hands-on experience.
I think jak will be ok on things like relays and logic boards because,
during the first series of this topic, he said when he tried to
activate the spindle all he would get would be a buzzing sound. Also I
understand there are two mechanically interlocked contactors for the
spindle. So, if I understand the circuit correctly, all of the rest of
the circuitry is used for control; which kind of leaves us with a power
problem.
However IHBKTBW.
On the other hand I worry a little bit about that fan problem. In the
past I've seen things like a fan set off a chain reaction, which in the
case of this type of electrical system where you have a TON of power
conversion (in a relatively small enclosure), would be the effect that
much heat would have on other components in the box. I'm guessing a
little here because I have no way of knowing if the fan and spindle are
powered by inter-related circuits which could mean when you fix the
spindle problem the fan will run.
dennis
in nca
p.s. Hey jac. Are you doing the voltage measurements at the motor and
while someone is holding down the motor start switch? Or are you
holding in the contactor mechanically?
.
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