Rutex drive issues, spi etc.
Posted by
rutexusa
on 2006-03-13 08:51:41 UTC
Gentlemen,
I do not normally watch this forum because of time constraints. One
of our customers tipped me off that we have received some negative
press here so I thought I should check in and comment.
I talked with Vladimir, at the Rutex office in Australia last evening
about some of the negative feed back we have received recently on
this forum and how he would want me to respond. I would say more,
but he encouraged me to be reserved in my comments.
The SPI has been the method that both the R9x and now the R2x drives
are tuned. The hardware end of the spi communication was pretty well
tested with the R9x series of drives, but our step up to windows has
presented a greater challenge for this mode of communication, and
Vladimir is close to having the issues resolved for the multiaxis
interpolation using spi. One thing we don't want at this time is to
have to address a myrad of questions about what will soon be released
regarding the R20x0 "spi" control of the drives. However, using the
dll, the user should be able to send high level commands similar in
control power to gcodes--directly to the Rutex mother board. The CNC
control will not have to worry about the co-ordinated interpolation.
The documentation and a few remaining bugs are being worked on at
this time. I will say that the full support of the features planned
for the R2000 series has taken longer to accomplish than expected,
but Vladimir assures me that we are getting close now.
A number of users have asked me questions about the spi that I cannot
answer. I just don't have the answers. Those I forward to the home
office, and I think that some of the response that some of the users
have had back has not been satisfying to them. In some cases, I
admit that I don't think the users received any response. This is
very hard for me to adjust to, but maybe there just is not a
practical answer to the questions they are asking yet, as the "spi"
has not been near completion until now. Vladimir is more comfortable
with programming and engineering than he is with talking with
customers. I enjoy talking to the creative people who use our drives
and helping them get their many different projects working. One of
our customers is using the Rutex drive to control the valve that
controls the liquid fuel used in their rocket!
I provide the first level of support for Rutex for people all over
the world except Australia and New Zealand. I also only provide very
limited support for the plasma system THC products that Rutex sells.
I try to email or phone every user who enquires on week days, and I
watch my emails to make sure that everyone gets a response. I did
not design these boards and I do run into questions occasionally that
I cannot answer. I forward these to the home office and try to make
sure they get answers there. If a question persists I call Vladimir
on the phone and get an answer.
As far as the "over-rating" of the drive is concerned, I will explain
what I have learned from providing support for the Rutex drives over
the last two years for these drives. (I have been a regular and
satisfied user of the Rutex drives for about 3 years now. I use both
the 20 amp and the 40 amp drives.) I believe the drives can "drive"
motors at the specified power levels if the motors have high enough
internal resistance. The limiting factor seems to be the diodes
built into the mosfets. When the motor is coming to a stop, the
motor can be generating a lot of power while the mosfets are all
turned off. Therefore if there is not enough resistance in the motor
circuit the protection diodes in the mosfets have to obsorb all of
this power. Therefore, for motors that do not have much internal
resistance Vladimir has specified the need for "braking resistors."
They are put in series with the motor leads. Typically they are one
or two ohms.
Rutex has posted a document entitled "Motor and drive matching" on
the Rutex.com web site under R2000 products which explains the need
for these braking resistors in low resistance motors and how they
affect performance. The need for these resistors is similar to that
of VFD braking resistors used in their drive systems. Most of what
the document says will apply to any pwm drive from any of the pwm
drive manufacturers with which I am familiar.
The first year and a half I provided support for the Rutex drives the
internal resistance was never a concern that I was aware of. However
when people started trying to drive huge motors with our drives we
began to see the need for these "braking resistors." Many people
look to the Rutex drives for higher power. My first experience was
with a user that was trying to drive huge servo motors that had .3
ohms of internal resistance. The motors were rated at 40 amps
continuous and 460 volts (I think). The user thought that if he just
dropped the voltage to under 200 volts he could use the R2020 drives
to run them. It just does not work that way.
Personally, I began using Rutex drives on SEM motors that had 2.5
ohms of internal resistance. Reliance motors that users often call
about sometimes even have as much as 4 ohms. However, many motors on
old mills that are being retrofit with Rutex drives have less than .4
ohms resistance so it is a serious issue for our drives.
Most of the time Rutex drives fail due to mistakes in making power
supplies or lack of consideration of the need for these braking
resistors. We are having trouble getting people take this need
seriously. We warrantee drives even when the users make what some
consider simple mistakes in wiring. We consider it part of the
learning curve in the industry we serve.
We warrantee drives that have failed after two years of use. I know
it because I make the decisions on what to warrantee. It is almost
always a full warrantee the first time. If a customer crams his
machine into the stop with no limit switches and blows a drive I will
warrantee the drive fully the first time he does that. If he does it
again and the drive is reparable, I may warrantee one half the price
of a new drive.
I am sorry that it has taken so long to get the "spi" features of the
R20x0 series working. Vladimir is focusing all of his attention to
getting this FINISHED. When I talked with Vladimir last evening
about the other products, he said he was not working on anything else
until the spi was "out the door." The spi has been his primary focus
since around the first of the year, although he did finish the R2030
brushless drive in January, and I have them in stock.
I haven't visited this forum regularly for a long time. My email
address is simple: Tom@...
I also welcome phone calls during normal business hours and evenings
at 573 368 7399.
I hope this helps. A lot of people, including myself are getting
good service out of Rutex drives.
Tom Eldredge
Rutex LLC
I do not normally watch this forum because of time constraints. One
of our customers tipped me off that we have received some negative
press here so I thought I should check in and comment.
I talked with Vladimir, at the Rutex office in Australia last evening
about some of the negative feed back we have received recently on
this forum and how he would want me to respond. I would say more,
but he encouraged me to be reserved in my comments.
The SPI has been the method that both the R9x and now the R2x drives
are tuned. The hardware end of the spi communication was pretty well
tested with the R9x series of drives, but our step up to windows has
presented a greater challenge for this mode of communication, and
Vladimir is close to having the issues resolved for the multiaxis
interpolation using spi. One thing we don't want at this time is to
have to address a myrad of questions about what will soon be released
regarding the R20x0 "spi" control of the drives. However, using the
dll, the user should be able to send high level commands similar in
control power to gcodes--directly to the Rutex mother board. The CNC
control will not have to worry about the co-ordinated interpolation.
The documentation and a few remaining bugs are being worked on at
this time. I will say that the full support of the features planned
for the R2000 series has taken longer to accomplish than expected,
but Vladimir assures me that we are getting close now.
A number of users have asked me questions about the spi that I cannot
answer. I just don't have the answers. Those I forward to the home
office, and I think that some of the response that some of the users
have had back has not been satisfying to them. In some cases, I
admit that I don't think the users received any response. This is
very hard for me to adjust to, but maybe there just is not a
practical answer to the questions they are asking yet, as the "spi"
has not been near completion until now. Vladimir is more comfortable
with programming and engineering than he is with talking with
customers. I enjoy talking to the creative people who use our drives
and helping them get their many different projects working. One of
our customers is using the Rutex drive to control the valve that
controls the liquid fuel used in their rocket!
I provide the first level of support for Rutex for people all over
the world except Australia and New Zealand. I also only provide very
limited support for the plasma system THC products that Rutex sells.
I try to email or phone every user who enquires on week days, and I
watch my emails to make sure that everyone gets a response. I did
not design these boards and I do run into questions occasionally that
I cannot answer. I forward these to the home office and try to make
sure they get answers there. If a question persists I call Vladimir
on the phone and get an answer.
As far as the "over-rating" of the drive is concerned, I will explain
what I have learned from providing support for the Rutex drives over
the last two years for these drives. (I have been a regular and
satisfied user of the Rutex drives for about 3 years now. I use both
the 20 amp and the 40 amp drives.) I believe the drives can "drive"
motors at the specified power levels if the motors have high enough
internal resistance. The limiting factor seems to be the diodes
built into the mosfets. When the motor is coming to a stop, the
motor can be generating a lot of power while the mosfets are all
turned off. Therefore if there is not enough resistance in the motor
circuit the protection diodes in the mosfets have to obsorb all of
this power. Therefore, for motors that do not have much internal
resistance Vladimir has specified the need for "braking resistors."
They are put in series with the motor leads. Typically they are one
or two ohms.
Rutex has posted a document entitled "Motor and drive matching" on
the Rutex.com web site under R2000 products which explains the need
for these braking resistors in low resistance motors and how they
affect performance. The need for these resistors is similar to that
of VFD braking resistors used in their drive systems. Most of what
the document says will apply to any pwm drive from any of the pwm
drive manufacturers with which I am familiar.
The first year and a half I provided support for the Rutex drives the
internal resistance was never a concern that I was aware of. However
when people started trying to drive huge motors with our drives we
began to see the need for these "braking resistors." Many people
look to the Rutex drives for higher power. My first experience was
with a user that was trying to drive huge servo motors that had .3
ohms of internal resistance. The motors were rated at 40 amps
continuous and 460 volts (I think). The user thought that if he just
dropped the voltage to under 200 volts he could use the R2020 drives
to run them. It just does not work that way.
Personally, I began using Rutex drives on SEM motors that had 2.5
ohms of internal resistance. Reliance motors that users often call
about sometimes even have as much as 4 ohms. However, many motors on
old mills that are being retrofit with Rutex drives have less than .4
ohms resistance so it is a serious issue for our drives.
Most of the time Rutex drives fail due to mistakes in making power
supplies or lack of consideration of the need for these braking
resistors. We are having trouble getting people take this need
seriously. We warrantee drives even when the users make what some
consider simple mistakes in wiring. We consider it part of the
learning curve in the industry we serve.
We warrantee drives that have failed after two years of use. I know
it because I make the decisions on what to warrantee. It is almost
always a full warrantee the first time. If a customer crams his
machine into the stop with no limit switches and blows a drive I will
warrantee the drive fully the first time he does that. If he does it
again and the drive is reparable, I may warrantee one half the price
of a new drive.
I am sorry that it has taken so long to get the "spi" features of the
R20x0 series working. Vladimir is focusing all of his attention to
getting this FINISHED. When I talked with Vladimir last evening
about the other products, he said he was not working on anything else
until the spi was "out the door." The spi has been his primary focus
since around the first of the year, although he did finish the R2030
brushless drive in January, and I have them in stock.
I haven't visited this forum regularly for a long time. My email
address is simple: Tom@...
I also welcome phone calls during normal business hours and evenings
at 573 368 7399.
I hope this helps. A lot of people, including myself are getting
good service out of Rutex drives.
Tom Eldredge
Rutex LLC