Resistor ID help

[Vwfan]

When I put the ohms meter up to it I got 45.5

[Vwfan]

Everything else on the board looks OK and I’ve looked at it very well so I’m assuming this is the only thing that’s bad

[eng199]

It's a 47 ohm wire-wound, probably 10watts.

I'm not so sure. Resistors are sometimes labeled with "K" where the "." would be, since "." is easy to miss or fail to print. If that is the case here, it is 5.47k ohm. A 5.47k with 240 volts across it would smoke unless it is over 10W, so that still checks out.

The second line is also unclear to me. Is it 15 or 150? Seems too small to be 15 watts.

[tblough]

My guess was manufacturer's series X5K and 47 ohm. 47ohm is a valid resistor value, 5.47K is not - 5K49 would be the closest. Based on his meter reading of 45.5 ohms, I'd say the 47ohm is correct. I'd also say the resistor is not the problem.

[centroid467]

Tom, that is my take on it as well. I am reading that as a 47 ohm. If anything is between the X5K and 47Ω, it looks like an underscore.

However, Matt is correct that you can find resistors marked similar to 5.47K. I have ceramic coated 3 watt wirewound resistors marked "2•2KΩ5%" and "4•7KΩ5%" in front of me that I grabbed from stock this morning.

[tblough]

I'm not disputing that resistors are marked with the decade symbol taking the place of the decimal point. I was just point out that 5.47 is not a valid resistor value, whether it's 5R47, 5K47, or 5M47. In the EIA resistor ranges, 5.49 is valid in the E48 and E192 ranges. 5.45 is not a valid resistor size in any range.

In the E24 range (5% resistors), 220 and 470 are valid sizes.

EIA Standard Values for Resistors and Capacitors
E3 50% tolerance (no longer used)
E6 20% tolerance (now seldom used)
E12 10% tolerance
E24 5% tolerance
E48 2% tolerance
E96 1% tolerance
E192 0.5, 0.25, 0.1% and higher tolerances

[eng199]

My guess was manufacturer's series X5K and 47 ohm. 47ohm is a valid resistor value, 5.47K is not - 5K49 would be the closest. Based on his meter reading of 45.5 ohms, I'd say the 47ohm is correct. I'd also say the resistor is not the problem.

Ok, good points. I also missed this:

When I put the ohms meter up to it I got 45.5

Now that I see this... I agree that the resistor is not bad.

[Muzzer]

That looks like the soft start resistor to me, sitting next to the soft start relay - but that's only a guess. These limit the inrush current when mains is applied. Once the bus caps are charged up, the relay shorts out the resistor and the VFD is ready for action. Often the resistor burns out because the relay isn't closing. This can be due to a variety of causes, including a failure of the circuit driving the relay. Hard to say what the issue is here but if the VFD still functions briefly, it is possible it could be something as simple as the relay failing, although this would be quite unusual.

The damage may be a bit more involved than simply replacing the resistor, in the same way that fuses generally only blow when something more significant fails, yet people persist in believing that replacing the fuse is likely to fix it. I guess you have little to lose (possibly your life, if you play your cards right) but if all else fails, you may need to simply buy a replacement VFD.

[Vwfan]

OK awesome thank you for the input yes I’ve already ordered a new one from automation direct I just figured I’d take a stab at trying to replace or repair this one I mean I know my way around electricity in the basic sense so I’m definitely not going to frame myself the worst that can happen as I damage the VFD further at that point I don’t think I have much more of a loss