Re: [Emc-users] VFD Braking Resistor
On Sat, 2007-08-04 at 01:23 -0500, RogerN wrote: > - Original Message - > From: "Kirk Wallace" <[EMAIL PROTECTED]> > To: "Enhanced Machine Controller (EMC)" > > Sent: Friday, August 03, 2007 10:49 AM > Subject: [Emc-users] VFD Braking Resistor > > > > Hello Roger, > > > > I have been working on my lathe spindle VFD, so I have been following > > your messages. I got it mostly working last night, and during testing, ... snip > > braking on your setup? > > > > Kirk Wallace > > > > Unfortunately my drive takes more than a dynamic braking resistor, mine > requires a dynamic braking unit. When the DC bus voltage gets to high, ... snip > faults by limiting my decel rates. It's good to hear that the dynamic > braking resistor does the job. My drive had DC injection braking, have > you experimented with that? > > Thanks! > > Roger Neal I figured you had a good reason for doing what you were doing. Now, I know what it is. The VFD's I have gotten so far, have had dynamic braking built in, so I don't know anything different. I am going to guess that DC injection braking is when, instead of letting the motor coast, the VFD invokes a reverse direction command for the duration of the deceleration, limited to the current and voltage limits of the normal drive circuit? I think in the long run, your work with using a PID loop with the spindle VFD will allow us VFD users to optimize the last bit of potential from these drives. Right now it seems like a balancing act between performance and setting limits that are safe but restrictive. Thanks. Kirk Wallace - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] VFD Braking Resistor
- Original Message - From: "Kirk Wallace" <[EMAIL PROTECTED]> To: "Enhanced Machine Controller (EMC)" Sent: Friday, August 03, 2007 10:49 AM Subject: [Emc-users] VFD Braking Resistor > Hello Roger, > > I have been working on my lathe spindle VFD, so I have been following > your messages. I got it mostly working last night, and during testing, > I > found that it was easy to have it error on deceleration. I happened to > have a large lab resistor on hand and in a matter of minutes, I had > the > dynamic braking working. It made a big difference. I plan on ordering > from Digikey three 50 Ohm 60 Watt resistors which will total under > twenty dollars. So, I am wondering, why you are avoiding using dynamic > braking on your setup? > > Kirk Wallace > Unfortunately my drive takes more than a dynamic braking resistor, mine requires a dynamic braking unit. When the DC bus voltage gets to high, dynamic braking dumps the power into a resistor converting that energy to heat. Some VFD's have the electronics to automaticaly dump the power in a resistor when the voltage gets too high, these drives only require the addition of a resistor. My drive requires a dynamic braking unit that connects directly to the DC bus terminals. When the bus voltage exceeds a certain voltage (the Hitachi DBU default is 362.5V) the braking resistor is switched into the circuit. I could buy a stove top element that would be sufficient for a dynamic braking resistor, but I also need a circuit to switch it on at high bus voltages and back off at normal bus voltage. A dynamic braking unit (bought or home made) is on my list of wants but for now I thought I should be able to eliminate faults by limiting my decel rates. It's good to hear that the dynamic braking resistor does the job. My drive had DC injection braking, have you experimented with that? Thanks! Roger Neal - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] VFD Braking Resistor
Hello Roger, I have been working on my lathe spindle VFD, so I have been following your messages. I got it mostly working last night, and during testing, I found that it was easy to have it error on deceleration. I happened to have a large lab resistor on hand and in a matter of minutes, I had the dynamic braking working. It made a big difference. I plan on ordering from Digikey three 50 Ohm 60 Watt resistors which will total under twenty dollars. So, I am wondering, why you are avoiding using dynamic braking on your setup? Kirk Wallace - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
