Please help! I fried my THC!!!
Posted: Thu Mar 28, 2024 7:20 pm
Today I finally got to firing my Plasma cutter as per the instructions on page 35 of the Acorn CNC Plasma Installation manual. Unfortunately it fried my THC!
I don't know what to do next as I feel like I have everything set up as it should be. Obviously somewhere something is wrong!
My Setup:
Acorn CNC Plasma with THC (Black)
- I am retrofitting an old 5'x10' CNC Router into a 5'x10' CNC plasma.
- The machine had SureStep Motors (STP-MTRH-34097) with DM860E drivers. I realize these are not the best, but they were already on the machine.
- I have ProPoint PROCUT 80A Plasma Cutter (I already had this before purchasing the Acorn.) This plasma cutter has a 50:1 voltage divider built in.
- I am using an ohmic touch sensor. I have a ring mounted on a solenoid which lowers down when I am measuring and pulls up and out of the way during the cut. The ring does not touch the plasma torch tip, but hangs just slightly higher than the tip. I have the ohmic touch sensor connected to T IN on the THC first going through output 5 which I have set to TorchTouchDisconnect. I used output 6 set to Ohmic Enable to lower the ring when measuring.
I do not have a float switch but am using ohmic only. If it fails, I have a TorchBreakaway.
Before hitting test fire:
- Made sure all grounding was followed as per the instructions. I put a ground bus on the frame which I connected the following to: A 10' ground rod hammered into the ground behind the machine. Ground of the Plasma cutter. Ground from the electrical power connection. The water table. The gantry.
- I tested the voltage out of the voltage divider. It peaked at 3.7 volts.
- I made sure that the Positive of the Voltage divider connected to the gnd of the THC and the negative connected to the ANLV on the THC.
- I made sure the Torch breakaway operated as it should.
- I made sure that the Ohmic sensor operated correctly. When I hit torch touch button my air cylinder lowered the ring, the torch lowered until the ring touched then the ring retracted. The height was correct after the procedure.
- I ran the THC live Scope. The orange line stayed basically at zero. When the machine moved a count of approximately 10 was measured in green line (far below the 50 counts allowed.)
When I hit test fire, there was a flash then smoke coming from the THC.
I double checked the voltage from the voltage divider and confirmed the 3.7 volt max and the polarity of the connection.
What do I do next? What could have fried the THC? Any help would be GREATLY appreciated!
![Crying or Very Sad :cry:](./images/smilies/icon_cry.gif)
I don't know what to do next as I feel like I have everything set up as it should be. Obviously somewhere something is wrong!
My Setup:
Acorn CNC Plasma with THC (Black)
- I am retrofitting an old 5'x10' CNC Router into a 5'x10' CNC plasma.
- The machine had SureStep Motors (STP-MTRH-34097) with DM860E drivers. I realize these are not the best, but they were already on the machine.
- I have ProPoint PROCUT 80A Plasma Cutter (I already had this before purchasing the Acorn.) This plasma cutter has a 50:1 voltage divider built in.
- I am using an ohmic touch sensor. I have a ring mounted on a solenoid which lowers down when I am measuring and pulls up and out of the way during the cut. The ring does not touch the plasma torch tip, but hangs just slightly higher than the tip. I have the ohmic touch sensor connected to T IN on the THC first going through output 5 which I have set to TorchTouchDisconnect. I used output 6 set to Ohmic Enable to lower the ring when measuring.
I do not have a float switch but am using ohmic only. If it fails, I have a TorchBreakaway.
Before hitting test fire:
- Made sure all grounding was followed as per the instructions. I put a ground bus on the frame which I connected the following to: A 10' ground rod hammered into the ground behind the machine. Ground of the Plasma cutter. Ground from the electrical power connection. The water table. The gantry.
- I tested the voltage out of the voltage divider. It peaked at 3.7 volts.
- I made sure that the Positive of the Voltage divider connected to the gnd of the THC and the negative connected to the ANLV on the THC.
- I made sure the Torch breakaway operated as it should.
- I made sure that the Ohmic sensor operated correctly. When I hit torch touch button my air cylinder lowered the ring, the torch lowered until the ring touched then the ring retracted. The height was correct after the procedure.
- I ran the THC live Scope. The orange line stayed basically at zero. When the machine moved a count of approximately 10 was measured in green line (far below the 50 counts allowed.)
When I hit test fire, there was a flash then smoke coming from the THC.
I double checked the voltage from the voltage divider and confirmed the 3.7 volt max and the polarity of the connection.
What do I do next? What could have fried the THC? Any help would be GREATLY appreciated!