On 2012-03-05, Oppie wrote:
"Gunner Asch" wrote in message
...
On Sat, 3 Mar 2012 09:36:30 -0500, "Oppie" wrote:
If you are seeing/hearing "motor slamming" where you didnt before..it
means you have rotational wear in your drive/gear train. Even with a
VFD..that wear will grow worse until its repaired. It will just grow
slower.
Yep, I already refurbished the motor shaft and bushings on the vari-drive
sheaves. That's now in good shape but wanted to minimize future wear due to
high starting torques.
Makes sense.
This is a 230/460V motor that is currently wired for 230V (Delta). The 460V
connection would be a Wye iirc. How are VFDs typically wired to the motor?
Is it a three wire or six wire connection? This is all new to me.
What I'm describing is for the USA for Bridgeport sizes machine
tools. Things are done differently in Europe.
I've never seen a VFD use six wires to the motor. And the VFD
does not care whether the motor is Delta or Wye -- as long as the
voltage is right.
For the 230/460 (or 240/480) motors, it is not a change between
Wye and Delta. That gives a voltage change which is not a factor of
two.
Instead, the motor typically has nine wires brought out, as
follows (use a fixed-pitch font to view the ASCII graphics to avoid
distortion):
First Winding Second Winding
+---WWWWWWWWWWWWW---(A) (D)---WWWWWWWWWWWWW---(G)
|
+---WWWWWWWWWWWWW---(B) (E)---WWWWWWWWWWWWW---(H)
|
+---WWWWWWWWWWWWW---(C) (F)---WWWWWWWWWWWWW---(I)
I've used letters instead of numbers, because the motors use numbers,
and I don't want to risk getting the location of the numbers wrong. You
can get the correct wiring information from the data plate on the motor.
Note that the left-hand end of all three of the "first winding"
group are tied together inside the motor housing where you can't access
them, and are not given a letter (or number) designation. You might
call it all 'Z' if you have to call it something. :-)
Now -- for the high voltage (460V in your listing) they are
wires as follows:
First Winding Second Winding
+---WWWWWWWWWWWWW---(A)+-------+(D)---WWWWWWWWWWWWW---(G)+--(L1)
|
+---WWWWWWWWWWWWW---(B)+-------+(E)---WWWWWWWWWWWWW---(H)+--(L2)
|
+---WWWWWWWWWWWWW---(C)+-------+(F)---WWWWWWWWWWWWW---(I)+--(L3)
The A-D and similar pairs are wired together and insulated in
the connection box. Only the G, H, and I ones are brought out to the
power line connections (through a switch, of course, if not from a VFD).
Now -- for the lower voltage, it is done differently.
First Winding Second Winding
+---WWWWWWWWWWWWW---(A)+-------------------------------------+----(L1)
| |
| +--+(D)---WWWWWWWWWWWWW---(G)+---+
| |
+---WWWWWWWWWWWWW---(B)+-------------------------------------+----(L2)
| | | |
| +--+(E)---WWWWWWWWWWWWW---(H)+---+
| |
+---WWWWWWWWWWWWW---(C)+-------------------------------------+----(L3)
| | |
+--+(F)---WWWWWWWWWWWWW---(I)+---+
Note that the D-E-F wires are connected together and insulated in the
wiring box. (I can't easily draw them jumping over the horizontal wires
without taking up even more space, so I'm mentioning it here to be
clear. Everywhere there is a '+' is a connection
And -- of course -- to make the motor run in reverse, you
exchange any two of the three L# wires. (Or, push the reverse button on
the VFD or the remote control wired to it.
Good Luck,
DoN.
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