Explainer video · TEMISA
Squirrel cage rotor repair: broken bars and end rings
Short answer
Squirrel cage rotor repair for broken bars covers a motor that starts late, runs hot and whose current swings. Copper or aluminum bars, joined by two end rings, crack next to the ring from start fatigue. A broken bar overloads its neighbors. TEMISA finds the damage with on-site current analysis and a growler test, replaces or re-brazes bars and rings, and balances the rotor to 15 tons against ISO 21940.
Key points
- Symptoms named in the video: a longer start, heat and current that swings.
- The cage has copper or aluminum bars joined by two end rings.
- The crack starts next to the ring, from repeated starts. A broken bar overloads its neighbors.
- Diagnosis: current signature analysis on site and a growler test in the shop.
- Bars and end rings are replaced or re-brazed, the rotor is tested, and it is balanced to 15 tons against ISO 21940.
Transcript
Your motor starts, but it doesn't pull like it used to: it takes longer, runs hot and the current swings. Often the cause is in the rotor: broken bars. A squirrel cage rotor has copper or aluminum bars joined by two end rings. Every start multiplies the current, so the bars heat up and expand. Start after start, fatigue cracks them next to the ring, until one breaks. And a broken bar overloads its neighbors, which fail faster. Here's how we fix it at TEMISA. First, diagnosis: current signature analysis on site and a growler test in the shop, to locate every damaged bar. Then we repair the cage: we replace or re-braze bars and end rings, and test the rotor. Since every repair shifts mass, we balance it on our bench, rated up to 15 tons, against ISO 21940. Your motor comes back with its report. At TEMISA we repair, rewind and balance industrial motors. Get a quote at temisa.mx
Frequently asked questions
How does a squirrel cage with broken bars behave?
The motor starts, but it takes longer to pull, runs hot and the current swings. The video places the cause in the rotor.
Why does a bar break?
Every start multiplies the current, so the bar heats and expands. Start after start, fatigue cracks it next to the end ring until it breaks. A broken bar overloads the bars beside it, and those fail faster.
What is the cage made of?
Copper or aluminum bars, joined by two end rings. The video does not lock the repair to one material.
How are the damaged bars found and repaired?
Current signature analysis on site and a growler test in the shop, to locate every damaged bar. Bars and end rings are then replaced or re-brazed, and the rotor is tested.
Why balance the rotor after the cage repair?
Because the repair shifts mass. The rotor is balanced on a bench rated up to 15 tons, against ISO 21940, and the motor comes back with its report.
Related
Video with images and narration generated with AI.
Request a quotation by email: ventas@temisa.mx. Phone: +52 33 3614 2460.