Made a phase converter 3 days ago
 

That was kind of a fun gig. Someone paid me $350 to make a pahse
converter out of parts that cost me about $50 (10 HP Baldor motor,
fused disconnect switch, oil caps etc). Took me about 1.5 hours to
do. This is a rope start phase converter with both legs balanced with
capacitors (90 uF per leg on a 10 HP idler).

At idle, the voltages were something like 243, 247, and 248 volts.

i

Made a phase converter 3 days ago
 

On 09/14/2010 07:54 AM, Ignoramus5013 wrote:
That was kind of a fun gig. Someone paid me $350 to make a pahse
converter out of parts that cost me about $50 (10 HP Baldor motor,
fused disconnect switch, oil caps etc). Took me about 1.5 hours to
do. This is a rope start phase converter with both legs balanced with
capacitors (90 uF per leg on a 10 HP idler).

At idle, the voltages were something like 243, 247, and 248 volts.

I'm confused. If you have capacitors handy for balancing, why can't you
switch one in as a start cap? Or does that just make for endless
complications?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

Made a phase converter 3 days ago
 

On 2010-09-14, Tim Wescott wrote:
On 09/14/2010 07:54 AM, Ignoramus5013 wrote:
That was kind of a fun gig. Someone paid me $350 to make a pahse
converter out of parts that cost me about $50 (10 HP Baldor motor,
fused disconnect switch, oil caps etc). Took me about 1.5 hours to
do. This is a rope start phase converter with both legs balanced with
capacitors (90 uF per leg on a 10 HP idler).

At idle, the voltages were something like 243, 247, and 248 volts.

I'm confused. If you have capacitors handy for balancing, why can't you
switch one in as a start cap? Or does that just make for endless
complications?


Here's what I know.

1. This Baldor motor does not start from all six of the balancing
capacitors connected to one leg (180 uF). It just does not.

2. The way I made the converter, it starts with a rope pull, and when
it runs it is well balanced, by three caps on one side and three caps
on the other (L1-L3 and L2-L3). It is quiet (all you hear is the
motor, fan etc, almost no humming).

3. To start this motor electrically, would require a starting circuit,
which is of course doable, but much more expensive for the buyer and I
did not have start caps on hand. This is not a sophisticated guy and
he is okay with rope start.

4. For some mystery reason, my own 10 HP Century motor in my own phase
converter, starts great from almost the same amount of capacitors (188
uF), but the 10 HP Baldor does not. So I was lucky with my phase
converter in that I did not need to have electrolytic caps for
starting.

The buyer's application is a 7.5 HP wood shaper and he told me that it
works very well with the RPC (I doubt he really would push it so far,
as to get full output from it).

i

Made a phase converter 3 days ago
 

On Tue, 14 Sep 2010 08:40:48 -0700 (PDT), "
wrote:

On Sep 14, 7:54*am, Ignoramus5013
wrote:
That was kind of a fun gig. Someone paid me $350 to make a pahse
converter out of parts that cost me about $50 (10 HP Baldor motor,
fused disconnect switch, oil caps etc). Took me about 1.5 hours to
do. This is a rope start phase converter with both legs balanced with
capacitors (90 uF per leg on a 10 HP idler).

At idle, the voltages were something like 243, 247, and 248 volts.

i

Are those voltages measured with out a load? Seem a bit high.

Paul

Perhaps his power company is like MY power company..the *******s...and
they deliver it high...often way way too high.

Which means my VFDs go into error and refuse to start.

Gunner


I am the Sword of my Family
and the Shield of my Nation.
If sent, I will crush everything you have built,
burn everything you love,
and kill every one of you.
(Hebrew quote)

Made a phase converter 3 days ago
 

Ignoramus5013 wrote:

3. To start this motor electrically, would require a starting circuit,
which is of course doable, but much more expensive for the buyer and I
did not have start caps on hand. This is not a sophisticated guy and
he is okay with rope start.

Years ago, like 1975 or so or, uncle sent me out to a friends place to look at his rpc.
Honking big 25 hp motor and rope start. Guy made a living grinding broaches like in
engine main bearings and camshaft bores.

Every morning, rope start, switch on the motor, switch on the grinders. I'm not sure he
even had caps on his system but it earned him a living until he retired years later.

Sometimes good enough is.

Wes

Made a phase converter 3 days ago
 

On 2010-09-14, Wes wrote:
Ignoramus5013 wrote:

3. To start this motor electrically, would require a starting circuit,
which is of course doable, but much more expensive for the buyer and I
did not have start caps on hand. This is not a sophisticated guy and
he is okay with rope start.

Years ago, like 1975 or so or, uncle sent me out to a friends place to look at his rpc.
Honking big 25 hp motor and rope start. Guy made a living grinding broaches like in
engine main bearings and camshaft bores.

Every morning, rope start, switch on the motor, switch on the grinders. I'm not sure he
even had caps on his system but it earned him a living until he retired years later.

Sometimes good enough is.


Yep. He must have been very strong.

I remember how in 1975 I was given a toy circus truck and took it all
apart. My mom was upset. I was 4

i

Made a phase converter 3 days ago
 

What's that Lassie? You say that Ignoramus5013 fell down the old
rec.crafts.metalworking mine and will die if we don't mount a rescue
by Tue, 14 Sep 2010 11:58:06 -0500:

3. To start this motor electrically, would require a starting circuit,
which is of course doable, but much more expensive for the buyer and I
did not have start caps on hand. This is not a sophisticated guy and
he is okay with rope start.

could you have added a second small motor to spin up the idler motor?
--

Dan H.
northshore MA.

Made a phase converter 3 days ago
 

On Wed, 15 Sep 2010 00:14:20 GMT, (dan) wrote:

What's that Lassie? You say that Ignoramus5013 fell down the old
rec.crafts.metalworking mine and will die if we don't mount a rescue
by Tue, 14 Sep 2010 11:58:06 -0500:

3. To start this motor electrically, would require a starting circuit,
which is of course doable, but much more expensive for the buyer and I
did not have start caps on hand. This is not a sophisticated guy and
he is okay with rope start.

could you have added a second small motor to spin up the idler motor?

Generally an old treadmill motor works pretty good for that.
Or a "starterator" from an old Kohler garden tractor motor

Made a phase converter 3 days ago
 

On 2010-09-15, dan wrote:
What's that Lassie? You say that Ignoramus5013 fell down the old
rec.crafts.metalworking mine and will die if we don't mount a rescue
by Tue, 14 Sep 2010 11:58:06 -0500:

3. To start this motor electrically, would require a starting circuit,
which is of course doable, but much more expensive for the buyer and I
did not have start caps on hand. This is not a sophisticated guy and
he is okay with rope start.

could you have added a second small motor to spin up the idler motor?

I could, but it would have cost him big bucks.

i

Made a phase converter 3 days ago
 

"Ignoramus5013" wrote in message
...
On 2010-09-15, dan wrote:
What's that Lassie? You say that Ignoramus5013 fell down the old
rec.crafts.metalworking mine and will die if we don't mount a rescue
by Tue, 14 Sep 2010 11:58:06 -0500:

3. To start this motor electrically, would require a starting circuit,
which is of course doable, but much more expensive for the buyer and I
did not have start caps on hand. This is not a sophisticated guy and
he is okay with rope start.

could you have added a second small motor to spin up the idler motor?

I could, but it would have cost him big bucks.

i

What are your product liability insurance costs ?

Best Regards
Tom.