Automation drives our daily activities. Household appliances such as washers and blenders to large industrial plants, electric motors provide the mechanical rotatory power that makes work easier. So when a machine stops working, there’s a high probability that the motor has broken down.
When a machine’s motor breaks down, you face the dilemma of either rewinding the AC motor or replacing it altogether. This is a difficult decision to make, and it mostly depends on the cost implications and extent of damage on the motor. What would tell you if your motor needs rewinding or replacement?
If your AC motor has stopped working or it’s not working efficiently, the first step toward addressing the problem is establishing its cause. After getting to the root of the problem, you’ll be in a position to decide whether the problem can be solved by AC motor rewinding or you’ll have to replace the motor. Motors mostly fail due to mechanical obstructions to their rotation or due to electrical inefficiencies from the motor windings. These electrical problems include overheating, broken wires, power surges, and excessive vibrations.
To know what’s making the problem, you’ll have to remove it from its housing to access its core, shaft and windings. Check if the bearings are working and if the motor shaft can rotate freely. Also, you need to check if the rotor is rubbing against the stator when rotating.
If you want to find out if there are electrical inefficiencies, you should start by measuring the insulation resistance of the winding. The manufacturer usually indicates the expected operating insulation resistance in the motor’s manual. If the insulation resistance you get after measuring deviates significantly from the manufacturer’s value, it’s an indication that the motor needs a rewinding. Also, check the windings for short circuits, low-quality wires, and broken wires.
Motor rewinding and efficiency
Some people still think that AC motor rewinding reduces the efficiency of the motor. However, rewinding a motor can increase its effectiveness if it’s done correctly. Adjustments include increasing or reducing the diameter or length of wire to increase the efficiency of an electrical winding. You could also keep the insulation resistance of a motor winding within the optimum range prevents overheating. Motor rewinding is an opportunity to increase the performance of your motor; the caveat is that it should be done by a professional and follow the industry’s best practices.
Motor rewinding or replacement?
The choice to rewind or replace all depends on the extent of the damage. Typically, the cost of rewinding a motor is 30 to 50 percent more than buying a new one; so if the cost is your primary consideration, you should go for rewinding. When evaluating the cost, don’t consider the upfront costs only; look into the long-term implications too. For example, consider how the power efficiency of the motor will change after rewinding and how often you use the motor. If the motor is used frequently, rewinding the motor could be more cost-effective than replacing it.
Replacing the motor makes sense when the damage on it is so extensive that repairing it exceeds that of buying a new one. Also, if the motor isn’t resolving your air conditioning needs, you should consider upgrading to one that suits your needs.