Phase converter
 

I haven't built a phase converter sence Fitch was a regular here. Now
I'm building one for "The Kid". He has his eye on a Haas VF2 with a 20
hp. spindle.

So, we've found a 5 hp. and a 20 hp. idler motors. The plan is to
start a 5, delay a few seconds then start a 20. I've done this with a
10 and a 15 for years, works great. I plan to pretty much copy the
Fitch designed unit but with different motors and circuit breakers
instead of fuses.

My questions
1. what size circuit breaker for a 220 VAC 3phase 5 hp motor

2. what size circuit breaker for a 220 VAC 3phase 20 hp motor
2b. what wire size for above motor

3. How much start caps for the 5 hp motor?

4. about how much run caps for the 25 hp system? I know we'll need to
tune it. Fitch got my other unit within 10 volts. I had a chance to
check it the other day, max volts was 252 L2-L3, lowest was 244 L1-L2,
don't remember the L1-L3 but it was in between. Now, I do wish I
remembered how he did it.


Karl

Phase converter
 

Karl Townsend wrote:

Now, I do wish I
remembered how he did it.

Karl

About like this:

http://wpnet.us/FitchWConverter.pdf

Phase converter
 

On 2013-06-20, Karl Townsend wrote:
I haven't built a phase converter sence Fitch was a regular here. Now
I'm building one for "The Kid". He has his eye on a Haas VF2 with a 20
hp. spindle.

So, we've found a 5 hp. and a 20 hp. idler motors. The plan is to
start a 5, delay a few seconds then start a 20. I've done this with a
10 and a 15 for years, works great. I plan to pretty much copy the
Fitch designed unit but with different motors and circuit breakers
instead of fuses.

My questions
1. what size circuit breaker for a 220 VAC 3phase 5 hp motor

FLA

2. what size circuit breaker for a 220 VAC 3phase 20 hp motor

FLA -- but how are you going to run them on two separate circuits,
when one starts another?

2b. what wire size for above motor

See FLA and AWG table

3. How much start caps for the 5 hp motor?

Try 100 uF, it differs from motor to motor as to how much will start it

4. about how much run caps for the 25 hp system? I know we'll need to
tune it. Fitch got my other unit within 10 volts. I had a chance to
check it the other day, max volts was 252 L2-L3, lowest was 244 L1-L2,
don't remember the L1-L3 but it was in between. Now, I do wish I
remembered how he did it.

I can find out how much is in my 17.5 HP phase converter (same
principle), it balances voltages great.

Phase converter
 

On Thu, 20 Jun 2013 18:37:59 -0500, "Pete C."
wrote:


Karl Townsend wrote:

Now, I do wish I
remembered how he did it.

Karl

About like this:

http://wpnet.us/FitchWConverter.pdf

BINGO, I never knew he wrote it up.


Thanks

Karl

Phase converter
 

On Thu, 20 Jun 2013 18:38:34 -0500, Ignoramus4976
wrote:

On 2013-06-20, Karl Townsend wrote:
I haven't built a phase converter sence Fitch was a regular here. Now
I'm building one for "The Kid". He has his eye on a Haas VF2 with a 20
hp. spindle.

So, we've found a 5 hp. and a 20 hp. idler motors. The plan is to
start a 5, delay a few seconds then start a 20. I've done this with a
10 and a 15 for years, works great. I plan to pretty much copy the
Fitch designed unit but with different motors and circuit breakers
instead of fuses.

My questions
1. what size circuit breaker for a 220 VAC 3phase 5 hp motor

FLA

2. what size circuit breaker for a 220 VAC 3phase 20 hp motor

FLA -- but how are you going to run them on two separate circuits,
when one starts another?

2b. what wire size for above motor

See FLA and AWG table

3. How much start caps for the 5 hp motor?

Try 100 uF, it differs from motor to motor as to how much will start it

4. about how much run caps for the 25 hp system? I know we'll need to
tune it. Fitch got my other unit within 10 volts. I had a chance to
check it the other day, max volts was 252 L2-L3, lowest was 244 L1-L2,
don't remember the L1-L3 but it was in between. Now, I do wish I
remembered how he did it.

I can find out how much is in my 17.5 HP phase converter (same
principle), it balances voltages great.

I googled FLA and found 20 amp and 60 amp breakers, sounds about
right. Never knew the term FLA before.

Don't see why you think a breaker for each motor is a problem, its
just there for a failure. I will be using an entire three phase load
center panel so he can breaker all his machines.

Phase converter
 

Karl Townsend wrote:

On Thu, 20 Jun 2013 18:38:34 -0500, Ignoramus4976
wrote:

On 2013-06-20, Karl Townsend wrote:
I haven't built a phase converter sence Fitch was a regular here. Now
I'm building one for "The Kid". He has his eye on a Haas VF2 with a 20
hp. spindle.

So, we've found a 5 hp. and a 20 hp. idler motors. The plan is to
start a 5, delay a few seconds then start a 20. I've done this with a
10 and a 15 for years, works great. I plan to pretty much copy the
Fitch designed unit but with different motors and circuit breakers
instead of fuses.

My questions
1. what size circuit breaker for a 220 VAC 3phase 5 hp motor

FLA

2. what size circuit breaker for a 220 VAC 3phase 20 hp motor

FLA -- but how are you going to run them on two separate circuits,
when one starts another?

2b. what wire size for above motor

See FLA and AWG table

3. How much start caps for the 5 hp motor?

Try 100 uF, it differs from motor to motor as to how much will start it

4. about how much run caps for the 25 hp system? I know we'll need to
tune it. Fitch got my other unit within 10 volts. I had a chance to
check it the other day, max volts was 252 L2-L3, lowest was 244 L1-L2,
don't remember the L1-L3 but it was in between. Now, I do wish I
remembered how he did it.

I can find out how much is in my 17.5 HP phase converter (same
principle), it balances voltages great.

I googled FLA and found 20 amp and 60 amp breakers, sounds about
right. Never knew the term FLA before.

Don't see why you think a breaker for each motor is a problem, its
just there for a failure. I will be using an entire three phase load
center panel so he can breaker all his machines.

The idlers end up wired in parallel anyway, if each is on it's own three
phase breaker in a three phase panel they're still in parallel. The only
oddity is that the main breaker into the panel (or main lugs) only has
two hot legs connected. You could even wire some run/balance caps in on
2 pole breakers and put a few meters on the panel cover so you can
dynamically adjust the balance.

Phase converter
 

On 2013-06-21, Pete C. wrote:

Karl Townsend wrote:

On Thu, 20 Jun 2013 18:38:34 -0500, Ignoramus4976
wrote:

On 2013-06-20, Karl Townsend wrote:
I haven't built a phase converter sence Fitch was a regular here. Now
I'm building one for "The Kid". He has his eye on a Haas VF2 with a 20
hp. spindle.

So, we've found a 5 hp. and a 20 hp. idler motors. The plan is to
start a 5, delay a few seconds then start a 20. I've done this with a
10 and a 15 for years, works great. I plan to pretty much copy the
Fitch designed unit but with different motors and circuit breakers
instead of fuses.

My questions
1. what size circuit breaker for a 220 VAC 3phase 5 hp motor

FLA

2. what size circuit breaker for a 220 VAC 3phase 20 hp motor

FLA -- but how are you going to run them on two separate circuits,
when one starts another?

2b. what wire size for above motor

See FLA and AWG table

3. How much start caps for the 5 hp motor?

Try 100 uF, it differs from motor to motor as to how much will start it

4. about how much run caps for the 25 hp system? I know we'll need to
tune it. Fitch got my other unit within 10 volts. I had a chance to
check it the other day, max volts was 252 L2-L3, lowest was 244 L1-L2,
don't remember the L1-L3 but it was in between. Now, I do wish I
remembered how he did it.

I can find out how much is in my 17.5 HP phase converter (same
principle), it balances voltages great.

I googled FLA and found 20 amp and 60 amp breakers, sounds about
right. Never knew the term FLA before.

Don't see why you think a breaker for each motor is a problem, its
just there for a failure. I will be using an entire three phase load
center panel so he can breaker all his machines.

The idlers end up wired in parallel anyway, if each is on it's own three
phase breaker in a three phase panel they're still in parallel. The only
oddity is that the main breaker into the panel (or main lugs) only has
two hot legs connected. You could even wire some run/balance caps in on
2 pole breakers and put a few meters on the panel cover so you can
dynamically adjust the balance.

Putting two parallel connected motors on two panel breakers makes zero
sense to me.

i

Phase converter
 

"Karl Townsend" wrote in message
...

On Thu, 20 Jun 2013 18:38:34 -0500, Ignoramus4976
wrote:
snip

4. about how much run caps for the 25 hp system? I know we'll need to
tune it. Fitch got my other unit within 10 volts. I had a chance to
check it the other day, max volts was 252 L2-L3, lowest was 244 L1-L2,
don't remember the L1-L3 but it was in between. Now, I do wish I
remembered how he did it.

I can find out how much is in my 17.5 HP phase converter (same
principle), it balances voltages great.

I googled FLA and found 20 amp and 60 amp breakers, sounds about
right. Never knew the term FLA before.

Don't see why you think a breaker for each motor is a problem, its
just there for a failure. I will be using an entire three phase load
center panel so he can breaker all his machines.

Don't forget the conversion between 3 phase and single phase amps, 3 phase
amps * 1.732 (square root of 3) = single phase amps. Also there is power
factor and efficiency to deal with.

RogerN

Phase converter
 

Putting two parallel connected motors on two panel breakers makes zero
sense to me.

i

its for failures. lets assume a wire insulation fails and contacts
ground. what do you want to have happen?.

Or a bearing burns out, or or or

Phase converter
 

Ignoramus4976 fired this volley in
:

Putting two parallel connected motors on two panel breakers makes zero
sense to me.

Hey! It makes perfect sense to me... then, whichever one exceeds the FLA
rating of its breaker first, it frees the other one up to fail
_almost_instantly_.

What better protection, than to have two breakers that protect one-
another? (and do nothing else useful that one couldn't?)

LLoyd

Phase converter
 

"Lloyd E. Sponenburgh" wrote:

Ignoramus4976 fired this volley in
:

Putting two parallel connected motors on two panel breakers makes zero
sense to me.

Hey! It makes perfect sense to me... then, whichever one exceeds the FLA
rating of its breaker first, it frees the other one up to fail
_almost_instantly_.

What better protection, than to have two breakers that protect one-
another? (and do nothing else useful that one couldn't?)

LLoyd

They let you manually start each motor.

The three phase panel is a nice backplane to build both the RPC itself
and the power distribution from the RPC on.

Phase converter
 

"Pete C." fired this volley in news:51c3a264$0$51623
:

They let you manually start each motor.

Breakers are not _usually_ designed to be switches. (some are, but I'm
betting this isn't the case, here).

SWITCHES are designed to be switches...

Lloyd

Phase converter
 

"Lloyd E. Sponenburgh" wrote:

"Pete C." fired this volley in news:51c3a264$0$51623
:

They let you manually start each motor.

Breakers are not _usually_ designed to be switches. (some are, but I'm
betting this isn't the case, here).

SWITCHES are designed to be switches...

Lloyd

If he uses a good panel like a QO those breakers are absolutely designed
for switching duty. It is very, very common to control warehouse
lighting banks directly with the circuit breakers.

Phase converter
 

On 2013-06-21, Karl Townsend wrote:

Putting two parallel connected motors on two panel breakers makes zero
sense to me.

i

its for failures. lets assume a wire insulation fails and contacts
ground. what do you want to have happen?.

Or a bearing burns out, or or or

Try to think how exacTLY the current will flow. For example, it may
want to flow to the big motor through the small breaker. Or, if the
small breaker trips, it will still get power through the big motor.

Phase converter
 

"Karl Townsend" wrote in message
...
I haven't built a phase converter sence Fitch was a regular here. Now
I'm building one for "The Kid". He has his eye on a Haas VF2 with a 20
hp. spindle.

So, we've found a 5 hp. and a 20 hp. idler motors. The plan is to
start a 5, delay a few seconds then start a 20. I've done this with a
10 and a 15 for years, works great. I plan to pretty much copy the
Fitch designed unit but with different motors and circuit breakers
instead of fuses.

If you check the actual hp of the spindle motor, you will likely find you
will *never* need the 20 hp idler.
Even if the motor were 20 hp, you'd have to be doing some big-time hoging to
warrant more idlers.
I run a Haas GR510 AND a Fadal 3016 off one 5 hp rpc, no pro'lengs, lite
work.
If some real work is brewing, I'll stage in another 5 hp.
I have over 30 hp in staged idlers, and can't remember switching in the
others, except to show off my switching/relay/cap circuitry.

It would be far more economical NOT to run that gonzo idler, but rather
stage 2, 3, 5 hp motors, switch them in as is needed.
Much more economical, and likely much better overall regulation.

I have my idlers started by motor starters, and breaker the wild legs
separately, ultimately feeding into the "main" generated leg supply.

Running big honking idler motors is like having a really big dick --
impressive in the locker room, but almost all women complain.
In the rpc case, your electric bill will complain. Esp. when yer doin 1/4
hp worth of drilling/tapping.....


My questions
1. what size circuit breaker for a 220 VAC 3phase 5 hp motor

2. what size circuit breaker for a 220 VAC 3phase 20 hp motor
2b. what wire size for above motor

3. How much start caps for the 5 hp motor?

4. about how much run caps for the 25 hp system? I know we'll need to
tune it. Fitch got my other unit within 10 volts.

At what load?
I've gotten mine and a buddy's within 1 volt, no load, a few volts at about
a 1-2 hp load -- different caps switched in, of course.

You should have two idenditcal banks of switchable caps, from 5 to 100 uF.
You can switch them in/out to L1-L3, L2-L3 as needed, whether for starting
or running, for a variety of load conditions..
Don't, however, switch caps in/out to electronic circuits while the circuits
are energized. Best to test with resistive loads. If you test with other 3
ph motors, THOSE 3 ph motors contribute to the generated-leg system, as
well, if they aren't directly loaded themselves.

I had a chance to
check it the other day, max volts was 252 L2-L3, lowest was 244 L1-L2,
don't remember the L1-L3 but it was in between. Now, I do wish I
remembered how he did it.

Trial and error, with the above.
--
EA




Karl

Phase converter
 

On Thu, 20 Jun 2013 19:55:25 -0500, "Pete C."
wrote:


"Lloyd E. Sponenburgh" wrote:

"Pete C." fired this volley in news:51c3a264$0$51623
:

They let you manually start each motor.

Breakers are not _usually_ designed to be switches. (some are, but I'm
betting this isn't the case, here).

SWITCHES are designed to be switches...

Lloyd

If he uses a good panel like a QO those breakers are absolutely designed
for switching duty. It is very, very common to control warehouse
lighting banks directly with the circuit breakers.

Correct.


--
""Almost all liberal behavioral tropes track the impotent rage of small
children. Thus, for example, there is also the popular tactic of
repeating some stupid, meaningless phrase a billion times" Arms for
hostages, arms for hostages, arms for hostages, it's just about sex, just
about sex, just about sex, dumb,dumb, money in politics,money in
politics, Enron, Enron, Enron. Nothing repeated with mind-numbing
frequency in all major news outlets will not be believed by some members
of the populace. It is the permanence of evil; you can't stop it." (Ann
Coulter)

Phase converter
 

Karl Townsend wrote:


Putting two parallel connected motors on two panel breakers makes zero
sense to me.

i

its for failures. lets assume a wire insulation fails and contacts
ground. what do you want to have happen?.

Or a bearing burns out, or or or

These are two different fault condition and are protected by two different
types of devices.

First of all, for motor branch circuit and breaker sizing, consult the NEC,
table 430.250 for the proper FLA. Don't use the nameplate. For a 220 VAC
3phase 5 hp motor, use 15.2 FLA. For a 220 VAC 3phase 20 hp motor, use 54
FLA. The

The motor overload protection should be set based upon the nameplate FLA.
The reasoning behind this is that, should you need to replace the motor,
the table value is conservative. So the conductors will be sized for a
worst case. On the other hand, the nameplate value is the limit for that
specific motor and needs to be reset in the event that the motor is changed
out.

Overload protection is for failures where the motor conductors themselves do
not suffer a fault but the motor seizes mechanically. The breaker is sized
to protect the branch circuit from an electrical fault.

Also, one must consider the need for a disconnecting means and their
requirements when designing a code compliant installation.

All of the above addresses three phase motor protection from a three phase
source. Phase converters are addressed by NEC Article 455. But this assumes
a device designed and listed as a phase converter. The calculations needed
to home brew such a system can be done, but that won't necessarily make for
a code compliant installation. Whether an inspector's buy-off is an issue
or not, I'll leave up to the individual.

--
Paul Hovnanian
------------------------------------------------------------------
Shoot low, sheriff. They're riding Shetlands!