viper
Titanium
- Joined
- May 18, 2007
- Location
- nowhereville
I was doing some RPC testing today for a friend. I am kind of thinking we are getting a little outside the operating tolerance on this one.
For reference, leg 3 is the wild leg
His idle voltages were 235, 258, 258.
I did not like it all that much loaded so we did a little tuning
Best I came up with was 235, 240, 248 unloaded
load with 1.5HP load 235, 240, 240
Problem is the inrush (spindle start) on his equipment (VFD) would pull the 1-3 down from 240V to 175V, plus when braking would shoot up to 280V. I did not discover any internal or external resistor but all other voltages were inline including the 2-3 which had a 220V inrush and 240V braking.
The RPC is 10HP, inrush current on L3 was 32A, was 80A on L1 (no check L2). They settle in with good voltages but I have concerns. I tuned the 1-3 all over the place and could not get the inrush voltage to go above 175V, mostly around 160-172V. Other voltages stayed tolerable.
1. Could there be a high resistance situation on L3 that could cause this? All connections look very good but still have to wonder.
2. This is a 7.5/10hp cnc spindle running on a 10hp converter, is this just asking too much?
3. brake voltage, this is the one that is puzzling me the most. All other voltages are fine but 1-3 spiking to 280-290V is concerning. This is a Fanuc drive. I am not sure if the RPC is unable to sink that level of power due to design or size and thus, the voltage is going high?
For reference, leg 3 is the wild leg
His idle voltages were 235, 258, 258.
I did not like it all that much loaded so we did a little tuning
Best I came up with was 235, 240, 248 unloaded
load with 1.5HP load 235, 240, 240
Problem is the inrush (spindle start) on his equipment (VFD) would pull the 1-3 down from 240V to 175V, plus when braking would shoot up to 280V. I did not discover any internal or external resistor but all other voltages were inline including the 2-3 which had a 220V inrush and 240V braking.
The RPC is 10HP, inrush current on L3 was 32A, was 80A on L1 (no check L2). They settle in with good voltages but I have concerns. I tuned the 1-3 all over the place and could not get the inrush voltage to go above 175V, mostly around 160-172V. Other voltages stayed tolerable.
1. Could there be a high resistance situation on L3 that could cause this? All connections look very good but still have to wonder.
2. This is a 7.5/10hp cnc spindle running on a 10hp converter, is this just asking too much?
3. brake voltage, this is the one that is puzzling me the most. All other voltages are fine but 1-3 spiking to 280-290V is concerning. This is a Fanuc drive. I am not sure if the RPC is unable to sink that level of power due to design or size and thus, the voltage is going high?