I have a milling machine that I acquired cheaply, due to a failed
sipndle VFD drive and burned out brake resistors.

The drive was professionally repaired and works great.

However, I am a little puzzled by the brake resistors. Yaskawa manual
only lists part numbers. I would like to find some suitable
replacements. What I need to know if the recommended ohms and watts. I
have some big-ass resistors in my ebay store that look like they might
fit, but I have no way of ascertaining what ohms/watts I need.

Thanks

I looked up some data, it looks like I need 40 Ohm, 392 watt resistor,
so I bought two 20 Ohm, 300 watt resistors on ebay, that should do
it.

i

On 2012-10-23, Ignoramus21608 wrote:
I have a milling machine that I acquired cheaply, due to a failed
sipndle VFD drive and burned out brake resistors.

The drive was professionally repaired and works great.

However, I am a little puzzled by the brake resistors. Yaskawa manual
only lists part numbers. I would like to find some suitable
replacements. What I need to know if the recommended ohms and watts. I
have some big-ass resistors in my ebay store that look like they might
fit, but I have no way of ascertaining what ohms/watts I need.

Thanks

On Mon, 22 Oct 2012 19:20:01 -0500, Ignoramus21608
wrote:

I have a milling machine that I acquired cheaply, due to a failed
sipndle VFD drive and burned out brake resistors.

The drive was professionally repaired and works great.

However, I am a little puzzled by the brake resistors. Yaskawa manual
only lists part numbers. I would like to find some suitable
replacements. What I need to know if the recommended ohms and watts. I
have some big-ass resistors in my ebay store that look like they might
fit, but I have no way of ascertaining what ohms/watts I need.

Thanks

Which VFD is on the drive?

Gunner

"The best government is a benevolent tyranny tempered
by an occasional assassination." --Voltaire

On 2012-10-23, Gunner wrote:
On Mon, 22 Oct 2012 19:20:01 -0500, Ignoramus21608
wrote:

I have a milling machine that I acquired cheaply, due to a failed
sipndle VFD drive and burned out brake resistors.

The drive was professionally repaired and works great.

However, I am a little puzzled by the brake resistors. Yaskawa manual
only lists part numbers. I would like to find some suitable
replacements. What I need to know if the recommended ohms and watts. I
have some big-ass resistors in my ebay store that look like they might
fit, but I have no way of ascertaining what ohms/watts I need.

Thanks

Which VFD is on the drive?

Gunner

"The best government is a benevolent tyranny tempered
by an occasional assassination." --Voltaire

Yaskawa 5 HP 230v

On Mon, 22 Oct 2012 21:57:40 -0500, Ignoramus21608
wrote:

On 2012-10-23, Gunner wrote:
On Mon, 22 Oct 2012 19:20:01 -0500, Ignoramus21608
wrote:

I have a milling machine that I acquired cheaply, due to a failed
sipndle VFD drive and burned out brake resistors.

The drive was professionally repaired and works great.

However, I am a little puzzled by the brake resistors. Yaskawa manual
only lists part numbers. I would like to find some suitable
replacements. What I need to know if the recommended ohms and watts. I
have some big-ass resistors in my ebay store that look like they might
fit, but I have no way of ascertaining what ohms/watts I need.

Thanks

Which VFD is on the drive?

Gunner

"The best government is a benevolent tyranny tempered
by an occasional assassination." --Voltaire

Yaskawa 5 HP 230v

Standard PC-3?

That should take a 30 ohm 500 watt resistor.

Gunner

"The best government is a benevolent tyranny tempered
by an occasional assassination." --Voltaire

On Mon, 22 Oct 2012 23:17:44 -0700, Gunner
wrote:

On Mon, 22 Oct 2012 21:57:40 -0500, Ignoramus21608
wrote:

On 2012-10-23, Gunner wrote:
On Mon, 22 Oct 2012 19:20:01 -0500, Ignoramus21608
wrote:

I have a milling machine that I acquired cheaply, due to a failed
sipndle VFD drive and burned out brake resistors.

The drive was professionally repaired and works great.

However, I am a little puzzled by the brake resistors. Yaskawa manual
only lists part numbers. I would like to find some suitable
replacements. What I need to know if the recommended ohms and watts. I
have some big-ass resistors in my ebay store that look like they might
fit, but I have no way of ascertaining what ohms/watts I need.

Thanks

Which VFD is on the drive?

Gunner

"The best government is a benevolent tyranny tempered
by an occasional assassination." --Voltaire

Yaskawa 5 HP 230v

Standard PC-3?

That should take a 30 ohm 500 watt resistor.


You can probably get away with using this one

http://www.ebay.com/itm/Aluminum-Enc...-/271087495712

since the mill wont be stopping as fast as the lathes I program the
Yaskawa VFDs to do.

Omniturn gets $150 for the 30 ohm duplicate btw.

And you CAN get away using a 250 watt, if you blow a muffin fan over
the resistor while the spindle/tool changer is in operation, in a
small well vented box.



Gunner

"The best government is a benevolent tyranny tempered
by an occasional assassination." --Voltaire

Ignoramus21608 wrote:

I have a milling machine that I acquired cheaply, due to a failed
sipndle VFD drive and burned out brake resistors.

The drive was professionally repaired and works great.

However, I am a little puzzled by the brake resistors. Yaskawa manual
only lists part numbers. I would like to find some suitable
replacements. What I need to know if the recommended ohms and watts. I
have some big-ass resistors in my ebay store that look like they might
fit, but I have no way of ascertaining what ohms/watts I need.
OK, assume the machine is 240 V. The DC bus voltage will be roughly
340 V DC. To stop the motor at normal 5 Hp rating, that is ~ 3700 W.
3700/340 = 10.9 A. So, a good choice would be a resistor bank that
draws 11 A at 340 V, or 31 Ohms. It will dissipate a peak of 3700 W,
but the average will be much lower. So, probably a couple hundred
Watts of resistor should handle it, even in rigid tapping duty, otherwise
it will never even get warm. You could put 3 100 Ohm resistors in
parallel, or 3 10 Ohm resistors in series.

Jon

On 2012-10-23, Jon Elson wrote:
Ignoramus21608 wrote:

I have a milling machine that I acquired cheaply, due to a failed
sipndle VFD drive and burned out brake resistors.

The drive was professionally repaired and works great.

However, I am a little puzzled by the brake resistors. Yaskawa manual
only lists part numbers. I would like to find some suitable
replacements. What I need to know if the recommended ohms and watts. I
have some big-ass resistors in my ebay store that look like they might
fit, but I have no way of ascertaining what ohms/watts I need.
OK, assume the machine is 240 V. The DC bus voltage will be roughly
340 V DC. To stop the motor at normal 5 Hp rating, that is ~ 3700 W.
3700/340 = 10.9 A. So, a good choice would be a resistor bank that
draws 11 A at 340 V, or 31 Ohms. It will dissipate a peak of 3700 W,
but the average will be much lower. So, probably a couple hundred
Watts of resistor should handle it, even in rigid tapping duty, otherwise
it will never even get warm. You could put 3 100 Ohm resistors in
parallel, or 3 10 Ohm resistors in series.

Jon

I bought two 20 ohm 300W resistors and I will connect them in series.

Ignoramus15542 wrote:



I bought two 20 ohm 300W resistors and I will connect them in series.
That ought to work. If you have it on the highest speed range and
stop, it may not absorb enough energy returned from the motor.
If that happens, you might get an over-voltage trip from the VFD.
You can slow the speed ramp-down, usually a parameter on the drive,
or go to one resistor for a 20 Ohm load. But, probably the 40 Ohms
will absorb enough energy and all will be well.

Jon

"Ignoramus21608" wrote in message ...
I looked up some data, it looks like I need 40 Ohm, 392 watt resistor,
so I bought two 20 Ohm, 300 watt resistors on ebay, that should do
it.


300 watt is probably going to be too low of wattage.

Electric water elements can be used in a pinch...

--just be sure and buy the kind that won't be damaged if they are operated while not submerged.

On 2012-10-23, PrecisionmachinisT wrote:

"Ignoramus21608" wrote in message ...
I looked up some data, it looks like I need 40 Ohm, 392 watt resistor,
so I bought two 20 Ohm, 300 watt resistors on ebay, that should do
it.


300 watt is probably going to be too low of wattage.

That's two 300 watt resistors == 600 watt combined.

i

Electric water elements can be used in a pinch...

--just be sure and buy the kind that won't be damaged if they are operated while not submerged.

One caution - the inductance will be additive - thus go ole XL .

I'd make the windings turn differently when mounting so they don't
enforce each others magnetic field.

Not much on 60 cycles or even DC. But the RF edges of the VFD might
see it and slow the dv/dt or the second derivative.

Martin

On 10/23/2012 3:49 PM, Ignoramus15542 wrote:
On 2012-10-23, Jon Elson wrote:
Ignoramus21608 wrote:

I have a milling machine that I acquired cheaply, due to a failed
sipndle VFD drive and burned out brake resistors.

The drive was professionally repaired and works great.

However, I am a little puzzled by the brake resistors. Yaskawa manual
only lists part numbers. I would like to find some suitable
replacements. What I need to know if the recommended ohms and watts. I
have some big-ass resistors in my ebay store that look like they might
fit, but I have no way of ascertaining what ohms/watts I need.
OK, assume the machine is 240 V. The DC bus voltage will be roughly
340 V DC. To stop the motor at normal 5 Hp rating, that is ~ 3700 W.
3700/340 = 10.9 A. So, a good choice would be a resistor bank that
draws 11 A at 340 V, or 31 Ohms. It will dissipate a peak of 3700 W,
but the average will be much lower. So, probably a couple hundred
Watts of resistor should handle it, even in rigid tapping duty, otherwise
it will never even get warm. You could put 3 100 Ohm resistors in
parallel, or 3 10 Ohm resistors in series.

Jon

I bought two 20 ohm 300W resistors and I will connect them in series.

"PrecisionmachinisT" writes:


I looked up some data, it looks like I need 40 Ohm, 392 watt resistor,
so I bought two 20 Ohm, 300 watt resistors on ebay, that should do
it.= 20
= 20

300 watt is probably going to be too low of wattage.

Electric water elements can be used in a pinch...

--just be sure and buy the kind that won't be damaged if they are =
operated while not submerged.

Why not immerse them in oil? Mineral oil will work.

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

On 2012-10-24, David Lesher wrote:
"PrecisionmachinisT" writes:


I looked up some data, it looks like I need 40 Ohm, 392 watt resistor,
so I bought two 20 Ohm, 300 watt resistors on ebay, that should do
it.= 20
= 20

300 watt is probably going to be too low of wattage.

Electric water elements can be used in a pinch...

--just be sure and buy the kind that won't be damaged if they are =
operated while not submerged.

Why not immerse them in oil? Mineral oil will work.


No thanks, I do not want a source ofa fire.

i

"Ignoramus27118" wrote in message
...
On 2012-10-24, David Lesher wrote:
"PrecisionmachinisT" writes:


I looked up some data, it looks like I need 40 Ohm, 392 watt resistor,
so I bought two 20 Ohm, 300 watt resistors on ebay, that should do
it.= 20
= 20

300 watt is probably going to be too low of wattage.

Electric water elements can be used in a pinch...

--just be sure and buy the kind that won't be damaged if they are =
operated while not submerged.

Why not immerse them in oil? Mineral oil will work.


No thanks, I do not want a source ofa fire.


Use to keep your coffee warm.

On 10/23/2012 9:24 PM, Gunner wrote:


Thanks for the heads up! Ive never seen a radiant heater like
that..but then..I live in California.

Gunner

Actually you probably have... I just described it poorly.

See http://www.porticus.org/bell/pdf/415-120_heater.pdf

Carla

I don't understand tongue piercings. If you want a speech impediment
that badly, go tell my barber that crewcuts are for pansies.

Many years ago my dad brought up a new radar station at White Sands.
It was a new design - a target tracking (automatic) radar.

Since the manufacture of the output tubes didn't want to drive the
antenna when testing the transmitter and verifying specs.

It was determined that a number (N) 1000 watt light bulbs to be used.

That was great, the transmitter was harsh on start up currents and
liked to over drive the filaments - new sets were pulled from stores
every other day for several weeks. Then it stopped and the real antenna
was attached for other tests. The purchasing guy had stocked up on a
volume discount deal - and then found out the bulbs went back to the
light poles.

Dummy loads are just an energy dump. The idea is to have the resistance
near the value needed so to much current won't be drawn and not to high
to prevent the power dump.

Martin

On 10/24/2012 5:47 PM, Carla Fong wrote:


On 10/23/2012 9:24 PM, Gunner wrote:


Thanks for the heads up! Ive never seen a radiant heater like
that..but then..I live in California.

Gunner

Actually you probably have... I just described it poorly.

See http://www.porticus.org/bell/pdf/415-120_heater.pdf

Carla

I don't understand tongue piercings. If you want a speech impediment
that badly, go tell my barber that crewcuts are for pansies.

"Ignoramus15542" wrote in message
...

Snip stuff.
I bought two 20 ohm 300W resistors and I will connect them in series.


Your 20 ohm 300 watt resistors in series will be 40 ohms at 300 watts.
If you parallel them, you will have 10 ohms at 600 watts.......Paul

On 10/24/2012 9:43 PM, Packratpaul wrote:
"Ignoramus15542" wrote in message
...

Snip stuff.
I bought two 20 ohm 300W resistors and I will connect them in series.


Your 20 ohm 300 watt resistors in series will be 40 ohms at 300 watts.
If you parallel them, you will have 10 ohms at 600 watts.......Paul


Uh, no... each discrete resistor can dissipate its rated power whether
in series or parallel... 600 watts either way, just 10 or 40 ohms
parallel or series...

Carla

Electile Dysfunction : the inability to become aroused over any of the
choices for president put forth by either party in the election.

"Carla Fong" wrote in message
...
On 10/24/2012 9:43 PM, Packratpaul wrote:
"Ignoramus15542" wrote in message
...

Snip stuff.
I bought two 20 ohm 300W resistors and I will connect them in series.


Your 20 ohm 300 watt resistors in series will be 40 ohms at 300 watts.
If you parallel them, you will have 10 ohms at 600 watts.......Paul


Uh, no... each discrete resistor can dissipate its rated power whether
in series or parallel... 600 watts either way, just 10 or 40 ohms
parallel or series...

Carla

Electile Dysfunction : the inability to become aroused over any of the
choices for president put forth by either party in the election.




Can I blame a brain fart? Blush....Paul

On 2012-10-25, Packratpaul wrote:

"Ignoramus15542" wrote in message
...

Snip stuff.
I bought two 20 ohm 300W resistors and I will connect them in series.


Your 20 ohm 300 watt resistors in series will be 40 ohms at 300 watts.
If you parallel them, you will have 10 ohms at 600 watts.......Paul



watts refer to power dissipation ability, it does not matter if they
are series or paralleled, they still can dissipate 600 watts.

i

Ignoramus10310 wrote:
On 2012-10-25, Packratpaul wrote:

"Ignoramus15542" wrote in message
...

Snip stuff.
I bought two 20 ohm 300W resistors and I will connect them in series.


Your 20 ohm 300 watt resistors in series will be 40 ohms at 300 watts.
If you parallel them, you will have 10 ohms at 600 watts.......Paul



watts refer to power dissipation ability, it does not matter if they
are series or paralleled, they still can dissipate 600 watts.

not talking series and parallel here, the 300 watt rating may or may not
not be what you expect, although it probably doesn't matter for this
application.

ohmite for example uses enron math in calculating power ratings for their
stuff.

Carla Fong writes:

Your 20 ohm 300 watt resistors in series will be 40 ohms at 300 watts.
If you parallel them, you will have 10 ohms at 600 watts.......Paul


Uh, no... each discrete resistor can dissipate its rated power whether
in series or parallel... 600 watts either way, just 10 or 40 ohms
parallel or series...


Correct.
--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Ignoramus27118 writes:

--just be sure and buy the kind that won't be damaged if they are =
operated while not submerged.

Why not immerse them in oil? Mineral oil will work.


No thanks, I do not want a source ofa fire.

If they are ANYWHERE near flash, you are doing something wrong.

And if that worried, buy a gallon of silicon such
as DOT-5 brake fluid with a 400F flash point
http://www.technicalchemical.com/msds/7012-6.pdf
--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

David Lesher wrote:

Ignoramus27118 writes:

--just be sure and buy the kind that won't be damaged if they are =
operated while not submerged.

Why not immerse them in oil? Mineral oil will work.


No thanks, I do not want a source ofa fire.

If they are ANYWHERE near flash, you are doing something wrong.


Or use a bigger braking resistor:

http://imgur.com/HvffT