Speed indicator light transformer is coded as which?

• A. U
• B. Ug
• C. Ugt
• D. Ur

Answer: (C)

In signaling equipment coding, the letters in a device’s code reveal its role and type. The first letter marks the broad group for signaling electrical devices, the second indicates the function related to indicators or lamps, and the third specifies the particular variant, like a transformer. A speed indicator light transformer combines the indicator/lamp function with a transformer, so its code uses the group for signaling gear (U), the indicator/lamps context (g), and the transformer aspect (t). Putting those together gives Ugt, which correctly identifies this item. This coding approach helps technicians quickly understand what the device is and how it’s used in the system, which is why the three-letter code with those markers best matches a speed indicator light transformer.