Got it, that’s good context to know for the future. Cheers
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timgunn1962
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For most applications, the HY will be fine. Out of the relatively cheap Far-East imports, it probably has the best manual, which makes a huge difference for a first-timer.
The only real-world benefit to using SV drives that I've encountered, is that they run motors smoothly at low speeds much better than basic V/Hz drives. If you are going to be running below about 10 Hz, SV makes sense, but not really otherwise. I did some testing of different VFDs on a lathe about 15 years ago. All the non-SV drives made the motor "coggy" below about 7 Hz and gave a poor machined finish. All the SV drives were smooth down to between 1 and 2 Hz and gave a nice finish.
What is yours running and what is your anticipated speed range?
To be fair, with a V/Hz (non-SV) drive, there are usually some parameters for low-speed Voltage boost that can be played with to improve low-speed operation. SV makes things easy by doing it automatically.
This will run a really low amp motor for an RJH Ferret tool grinder. Again, massive overkill but the actual end goal of this setup will be to swap it to a surface grinder or small lathe. For now, with the Ferret I may use the frequency control to see if I can dual purpose the grinder as a lap for carbide scraper blades with fine micron diamond paste, but it’s a 2 pole motor and apparently you shouldn’t run them under 20hz frequency or something. I’ll try it anyway to see what the lowest lapping speed with required torque could be achieved. Its primary use will be at full or half speed with a decently fine diamond wheel.
In regards to the future, I am definitely sensitive to using a VFD on a surface grinder to get decent finish so I would probably swap the VFD out for something higher quality anyway. This HY will probably end up on a saw, lathe or drill.
In regards to the future, I am definitely sensitive to using a VFD on a surface grinder to get decent finish so I would probably swap the VFD out for something higher quality anyway. This HY will probably end up on a saw, lathe or drill.
For what it’s worth I got this back from Schaffner regarding overload capability of their EMI, I’ll stick it on here in case Google brings anyone to this thread and it could help them:
“Please see our standard overload current curve attached.
It should be understood as follows:
Example: If you look at 10ms at 50°C the overload current could be 16 x IN (A) , meaning the overload capability of a 10A filter would be 160A for 10ms.”
“Please see our standard overload current curve attached.
It should be understood as follows:
Example: If you look at 10ms at 50°C the overload current could be 16 x IN (A) , meaning the overload capability of a 10A filter would be 160A for 10ms.”
A good old Clough over-engineered video.
I was just going to post that a 10A filter would be more than good enough, as they don't suddenly release magic smoke above their rated current.
2.2KW is less than 10A at 240V, and even allowing for VFD inefficiency, you are highly unlikely to ever exceed 10A during normal use.
The 16A listed in the manual is due to inrush current, and to ensure some margin to avoid false trips under high loads.
For home use, I'd just wire in an easily accessible master switch (or just straight into a 13A plug).
A contactor doesn't really give you any additional benefit, and from a practical point, there is no need or benefit to disconnecting single phase neutral, but if you really are concerned about it, a double pole master switch isn't going to be much more expensive than a single pole switch.
(You have to remember most of these VFD manuals are written from the point of 3 phase, or for the possibility of the input being split phase, whereby you really do want to disconnect all power in)
Just make sure you have your stop button circuit using NC switches, so if a wiring/button fault does occur, the VFD won't start or will just stop, and if you feel that a fast stop is needed, fit an E-stop button that triggers the VFD fast stop, instead of the normal slower ramp down stop.
The probability of even a cheap VFD failing to stop when needed, is probably even less than of a conventional NVR switch/contactor sticking on.
A VFD is far more likely just to die, than fail to stop when needed, provided the control circuit has been configured correctly.
I was just going to post that a 10A filter would be more than good enough, as they don't suddenly release magic smoke above their rated current.
2.2KW is less than 10A at 240V, and even allowing for VFD inefficiency, you are highly unlikely to ever exceed 10A during normal use.
The 16A listed in the manual is due to inrush current, and to ensure some margin to avoid false trips under high loads.
For home use, I'd just wire in an easily accessible master switch (or just straight into a 13A plug).
A contactor doesn't really give you any additional benefit, and from a practical point, there is no need or benefit to disconnecting single phase neutral, but if you really are concerned about it, a double pole master switch isn't going to be much more expensive than a single pole switch.
(You have to remember most of these VFD manuals are written from the point of 3 phase, or for the possibility of the input being split phase, whereby you really do want to disconnect all power in)
Just make sure you have your stop button circuit using NC switches, so if a wiring/button fault does occur, the VFD won't start or will just stop, and if you feel that a fast stop is needed, fit an E-stop button that triggers the VFD fast stop, instead of the normal slower ramp down stop.
The probability of even a cheap VFD failing to stop when needed, is probably even less than of a conventional NVR switch/contactor sticking on.
A VFD is far more likely just to die, than fail to stop when needed, provided the control circuit has been configured correctly.
daleyd
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You can easily spend a day on control.com looking into this, for work purposes I only implement what other people tell me (machine safety is a whole qualification in itself and if it was my name down on the design without having the right bits of paper then in the event of someone getting hurt then old beaky would have a field day) so I don’t really have much say in it.
For home use I’m marginally more comfortable with power going off, if nothing else it also acts as a no volt release for the whole system as well meaning power doesn’t come on until I hit the reset button. But to be honest it also wouldn’t bother me just using the stop input - take your pick, it’s whatever you feel comfortable with.
Going back a previous question, though it’s not something I’ve seen myself there are actually posts on control.com discussing the merits of power off vs stop input exactly because of drives failing to stop - so it seems it does happen, though admittedly you’d have to be pretty unlucky.
For home use I’m marginally more comfortable with power going off, if nothing else it also acts as a no volt release for the whole system as well meaning power doesn’t come on until I hit the reset button. But to be honest it also wouldn’t bother me just using the stop input - take your pick, it’s whatever you feel comfortable with.
Going back a previous question, though it’s not something I’ve seen myself there are actually posts on control.com discussing the merits of power off vs stop input exactly because of drives failing to stop - so it seems it does happen, though admittedly you’d have to be pretty unlucky.
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We had to do a 3 day course at one of the robot manufacturers to qualify to work on the safety side, if they deemed you capable you were issued with a unique ID that allowed you log in to the software which meant any changes could be traced to a person.
daleyd
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I’ve designed some stuff for heater safety, which I’m ok with. I don’t really put my name to anything to do with rotating machinery other than I’ll do the programming based on what someone else (usually TUV safety qualified) decides how the safety side operates. We looked into me doing the course a few years back but we don’t do enough to justify the fairly considerable expense so we just get someone else to do it. My previous place had just started to use Siemens Sirius safety plc when I was leaving, about 12-13 years ago now, for speed monitoring and standstill detection on paper unwinding machinery.
I’ve just done some panels for a company using Schneider programmable safety controllers, which was quite interesting. Compared to hardwired safety relays they are very flexible (sick, pile etc all do similar nowadays)) They did all the safety risk assessments and I implemented what they asked for - perfect!
I’m definitely more comfortable being able kill the power completely to the machine in arms reach considering I’ve not got much know how and I did it myself
and the Chinese drive aspect doesn’t fill me with joy but does a job 