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edj
@edj
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Joined: Jan 15, 2025
Last seen: Sep 19, 2026
Topics: 5 / Replies: 15
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RE: PowerFlex 525 F004 undervoltage on several drives at the same second

A 200hp across the line on the same transformer is your brownout. Six times FLA for a second or two, the transformer sags, the DC bus on the drives dr...

2 minutes ago
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RE: Modbus RTU RS-485 to six meters on a MicroLogix 1400, timeouts on the far three

120 ohm across the 1400 terminals, bias jumper on. Swapped + and minus on 4 and 5 after checking which side sat high with the meter. 4 and 5 read now....

37 minutes ago
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RE: Star-delta, soft starter or VFD for a 45 kW compressor

Soft starter it is, 45kW with the bypass, pressure switch stays as it was. Started it this morning with a clamp on the motor lead, door open, gloves a...

40 minutes ago
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RE: DeviceNet 1756-DNB error 91 bus-off a few hours after conduit rework

Warmer copper, more loss. Or just day shift. Either way it's fixed.

3 hours ago
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RE: PowerFlex 755 input phase loss fault on a hot afternoon

Continuity isn't the test. A fuse can read zero ohms on a meter and still have half its element gone. High resistance under 90 A drops volts, and it's...

3 hours ago
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RE: 1769-OB16 transistor outputs dying one by one on a relay panel

What's on the relay sockets? Any little module clipped across the coil terminals, a diode, an RC? And the coils are DC, not AC through a rectifier?

5 hours ago
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RE: Plant kWh total in a CompactLogix went to minus 2 billion after 24 days

Did the kWh carry like Scott said, REAL sub total into a DINT kWh, and seeded the DINT from the meter's own register so the report doesn't start from ...

6 hours ago
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RE: Modbus RTU RS-485 to six meters on a MicroLogix 1400, timeouts on the far three

A to B idle at meter 6, 0.02 V. Nothing there. At the panel end it's 0.2 V. Meters 4 and 5 are a newer batch, terminals say + and minus instead of A a...

6 hours ago
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RE: Star-delta, soft starter or VFD for a 45 kW compressor

Pressure switch and the unload solenoid, that's the whole controller. There's nothing on it that could take a speed reference, and the compressor vend...

11 hours ago
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RE: Plant kWh total in a CompactLogix went to minus 2 billion after 24 days

DINT, says so in the tag list. Historian has 2,147,480,112 at 05:58 and then -2,147,428,851 at 05:59. The meter's own kWh reads 2,148,900 since it was...

12 hours ago
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RE: DeviceNet 1756-DNB error 91 bus-off a few hours after conduit rework

Meter it before you guess. Network power off, ohms between CAN_H and CAN_L at the scanner tap.

3 days ago
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