Repair TECO VFD?

DaveinAlabama

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I have a TECO 7300CV VFD which was damaged by a loose wire on the power input shorting out. The troubleshooting flowchart in the manual says that I need to replace the “burst absorber”. I took the unit apart and didn’t see any discolored parts, and there are no parts that are removable (everything is soldered to the board).
This model is discontinued, but my Microkinetics CNC Express mill requires this exact driver (model number JNTHBCBA0002AC-U). Eventually they will have software to allow use of a TECO L510 VFD, but that’s not ready yet. TECO 7300 doesn’t seem to be available new, but I just bought one off eBay.
Any advice on repair or replacement would be appreciated.
Thanks,
Dave
 
The burst absorber is not part of the VFD it is added as a surge absorber external to the VFD used across the contactor. If power is directly wired to your VFD input, then you do not have one. Most likely you damaged the power input section of the VFD, hard to tell but the input power section is not user replaceable on most smaller VFDs. I would check with Microkinetics CNC if something like the Teco E510 could be used, as it is the replacement series for the 7300/N3 series. The 7300 has been discontinued for several years, they should have an alternate newer VFD they recommend. Sourcing older VFDs that have not been used for some time can often blow their capacitors on powering them up because of degradation of the electrolytic capacitors over time.

Burst Absorber.jpg
 
Thanks for the reply. I spoke with Microkinetics today and while they are working on making their software compatible with the Teco 510, it currently is not. They advised me that the only solution that works with their controller output is to find anofher 7300CV.
I'll keep looking for a new one, and hopefully the one I bought on eBay won't blow its
capacitors.
 
The burst absorber is not part of the VFD it is added as a surge absorber external to the VFD used across the contactor. If power is directly wired to your VFD input, then you do not have one. Most likely you damaged the power input section of the VFD, hard to tell but the input power section is not user replaceable on most smaller VFDs. I would check with Microkinetics CNC if something like the Teco E510 could be used, as it is the replacement series for the 7300/N3 series. The 7300 has been discontinued for several years, they should have an alternate newer VFD they recommend. Sourcing older VFDs that have not been used for some time can often blow their capacitors on powering them up because of degradation of the electrolytic capacitors over time.

View attachment 303923

I'm working on my new control box for my CNC Mill/Drill project and have a question about this burst absorber part. How much current would you need to be running to need one of these? I have a circuit breaker and a relay switch I was going to use with the VFD I'm running the spindle from. The spindle is only 0.55kW so not very much current but still if it's something I should have in the circuit I'd like to find one.

Thanks,

John
 
Kind of different animals, the burst absorber prevents the reverse spike associated when the contactor releases from its energized state. The spike is momentary and can be upwards of 200V from the coil causing the reverse voltage spike. In general both contactors and relays have a plug in diode/RC or similar absorber to shunt the reverse spike. Separate to this in particular in CNC with sensitive electronics that share the same power source is to use an EMI/RFI filter on the power line going to the VFD, also fusing which is quicker acting then a breaker. Typically I use high speed fusing like CC fuses or J class, but this is VFD specific. I also use noise filters in a lot of my builds, often Lambda/TDK in smaller applications.
 
Kind of different animals, the burst absorber prevents the reverse spike associated when the contactor releases from its energized state. The spike is momentary and can be upwards of 200V from the coil causing the reverse voltage spike. In general both contactors and relays have a plug in diode/RC or similar absorber to shunt the reverse spike. Separate to this in particular in CNC with sensitive electronics that share the same power source is to use an EMI/RFI filter on the power line going to the VFD, also fusing which is quicker acting then a breaker. Typically I use high speed fusing like CC fuses or J class, but this is VFD specific. I also use noise filters in a lot of my builds, often Lambda/TDK in smaller applications.

Thank you, that gives me much to think about. I currently have a very rudimentary control system using a cheap 5-axis board and TB6600 drives to some donated Nema 23 steppers. Once I get the mechanical aspects of this build squared away (by that I mean trammed;)) I'll upgrade to the Mesa 7i96 I bought, some bigger steppers and drives. Getting the support electrical right is a big thing for me.

John
 
There are a lot of dealers that sell used VFD's. Google that and you'll see. I can't remember the name of the dealer I bought a used Lenze from, but he was in NJ, he guaranteed them, had different brands, and it's been on my mill for years now at less than 1/2 the price of a new one.
 
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