Automatic Electric Ltd. v. R.K. Dhawan — "Dimmerstat" Trademark Case

Citation & Court

Automatic Electric Limited v. R.K. Dhawan & Anr., Delhi High Court, 1994.

The Dispute

Automatic Electric had used the registered mark "DIMMERSTAT" for variable-voltage auto-transformers since 1945, building up substantial goodwill through sales and advertising. The defendants began using "DIMMER DOT" for a similar product and, when sued for infringement, argued that "DIMMER" was a generic term for the product category and therefore could not be monopolised.

What the Court Held

The Delhi High Court rejected the genericness defence. On the evidence, "DIMMER" had not been shown to be generic in the specific context of variable-voltage auto-transformers. The Court also compared the marks as composite wholes — "DIMMERSTAT" against "DIMMER DOT" — rather than isolating the shared word, and noted pointedly that the defendants' own attempt to claim proprietary rights in "DIMMER DOT" undercut their argument that "dimmer" was merely generic.

How to Use This in Your Reply

Use this as the counterweight to J.R. Kapoor v. Micronix India above: a shared word defence only works if genericness in that specific trade is actually proven, not merely asserted. It's also a useful citation against a defendant who simultaneously claims a word is generic and tries to assert their own exclusive rights in a mark built around that same word.

Key takeaway: Whole-mark comparison, not word-isolation, decides infringement — and a genericness defence needs trade-specific evidence, not assertion.