Haas DS30 destroyed 2 encoders within 10 days

My Haas DS30 is eating encoders on the live tool. The live tool motor is a Yaskawa. It's a pretty popular servo. It was replaced with a brand new, entire motor, twice, in 10 days. The loads I'm putting on the server motor are hardly anything.

After the motor gives a TT encoder error on the machine (says it's an encoder cable fault), I took the motor and plugged it into another axis and the other axis showed the same exact fault... So I know it's definitely not a cable fault.

I've checked the resistance on both servo motors on the high voltage side and it is fine. I also checked the resistance on the HV cable and that is fine as well. I measured the resistance on the encoder cable as well... That is fine as well.

I've swapped x-axis and live tool amps to rule that out. Behavior was the same on both amps. The second servo motor actually stopped working and through the alarm while I had the x-axis amp running the live tool.

I've also gone and put ferrite rings on all the associated cable connections to the MoCons... As well as separated as best I could the HV and encoder cables in the machine and where they route out to the axis

The only thing I can think of that is doing this is some type of high voltage spike is entering the encoder via the cable and killing the encoder.

I talked to Haas a few times and they are not sure what the problem could be besides a bad cable.

When you look at both encoders, by removing the encoder covers, they are very clean and dry... Indicating they are not getting any type of contamination in there to stop them from working correctly.

Once the encoder throws the TT alarm, the server motor is done. The original servo motor lasted 11 years so something has definitely changed! Is it really sounding like a bad cable? Any ideas would be appreciated!



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Seems like you know what you are talking about with voltages. What kind of power do you have coming in to your shop? I mean, are you on a residential transformer or comercial? If comercial are you on a private transformer? I have seen shared commercial transformers wipe out several machine boards at the same time. A welder was in the next bay using a hi-freq tig and it wreaked havoc.

Seen the same thing on residential units with phase converters also. pulling a load and neighbor turns something off in their house and you get a surge.

Timeline is everything. I bet its the cable

resistance doesn't matter when there is no load on the cable, id bet the connectors are at fault on the cable. Replace the cable.... resistance only goes up when there is a load going through it.

I ordered a cable today and will replace it. I'm cautiously optimistic !

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