Horned Toad
Member
Greetings all!
I have read a good deal about PLC programming that is still way over my head, and I'm very greatful for the opportunity to benifit from the experience here at :site: . I wanted to play on this experience and contribuate a couple of things that I have come to discover for myself. First, There is no question as to the value of PLC's in automation and other compicated processes. It is becoming more frequent that I install small units to replace older technology like mechanical sequence timers, and "one off" controllers. I have found that in many instances a manufacturer will design a application specific control that is hard to find and expensive to replace. The beautiful thing about the newer "micros" is that they are generic in nature and are a plentiful, reliable, and unquestionably inexpensive alternitive!
VFD's.....At the facility where I work the majority of the machinery is non-domestic. This translates to long wait times, and considerable expense for replacement parts. One specific application uses a small gearmotor with a intergral brake. It is a 480 volt motor ( .48 kw I think )with a 480 brake mounted on the tail shaft. The brake coil on these units have rely on the motors overload protection since they are both fed from the same feed. As a result I send in a few motors to the motor shop with damaged brake coils. The OEM supplier announced that they will no longer sell coils seperately, and this application specific gearmotor is around $3K. The motor shop cannot remanufacture the coils because of careful engineering. My solution has been to toss the brakes completely and use a DIN rail mount VFD's versitility to run boththe motor and control the braking. And... I gained the ability to vary the motors speed! So in this application I chose a VFD not primarily to control a motor but more to control a brake.
I would be interested to hear of other non-typical applications for both PLC's and VFD's
I have read a good deal about PLC programming that is still way over my head, and I'm very greatful for the opportunity to benifit from the experience here at :site: . I wanted to play on this experience and contribuate a couple of things that I have come to discover for myself. First, There is no question as to the value of PLC's in automation and other compicated processes. It is becoming more frequent that I install small units to replace older technology like mechanical sequence timers, and "one off" controllers. I have found that in many instances a manufacturer will design a application specific control that is hard to find and expensive to replace. The beautiful thing about the newer "micros" is that they are generic in nature and are a plentiful, reliable, and unquestionably inexpensive alternitive!
VFD's.....At the facility where I work the majority of the machinery is non-domestic. This translates to long wait times, and considerable expense for replacement parts. One specific application uses a small gearmotor with a intergral brake. It is a 480 volt motor ( .48 kw I think )with a 480 brake mounted on the tail shaft. The brake coil on these units have rely on the motors overload protection since they are both fed from the same feed. As a result I send in a few motors to the motor shop with damaged brake coils. The OEM supplier announced that they will no longer sell coils seperately, and this application specific gearmotor is around $3K. The motor shop cannot remanufacture the coils because of careful engineering. My solution has been to toss the brakes completely and use a DIN rail mount VFD's versitility to run boththe motor and control the braking. And... I gained the ability to vary the motors speed! So in this application I chose a VFD not primarily to control a motor but more to control a brake.
I would be interested to hear of other non-typical applications for both PLC's and VFD's
