Under the condition of high humidity, when the gear motor that has been not used for a period of time is activated again, it will found that the insulation resistance of the winding of the gear motor is reduced and even as low as zero. In this case, drying process should be carried out to make the insulation resistance and absorption ratio to reach the specified value. If the gear motor affected with damp is put into operation rashly, it is possible to cause the insulation breakdown of the coils of gear motor and result in an accident. Now let me introduce the way of drying the gear motor affected with damp.
Drying Using Electric Welding Machine
Before operation , connect the connection heads of the winding of gear motor affected with damp in series, and ground the casing, so that the three groups of winding can be heated and dried.An ammeter can be connected to observe whether the current of gear motor reached the rated current. Using AC welding machine to dry the gear motor does not require disassembly the gear motor, reducing the workload. At the same time, under the condition of electricity, the gear motor heats up with its own resistance, so that the coils can be even heated and the drying effects is better. But the method is only applicable to some gear motors and can not be used for a long time, because the welding machine may be burnt out due to the excessive current applied to the transformer of welding machine.
The operating wiring of DC welding machine is similar to AC welding machine, and the ammeter connected shall be DC ammeter. It’s convenient to dry the gear motor affected with damp using DC welding machine, and DC welding machine can dry large and medium-sized gear motor and high-voltage gear motor for a long time because the internal components of DC welding machine will not be damaged due to a long-term or a high-current operation. It’s worth noting that all contact points are supposed to be in good contact and tight when using above two methods for drying. Special wires should be used for the outgoing wires of welding machine, and the required section size shall meet the current carrying capacity of the welding machine output current.
Heating Using External Heat Source
The gear motor affected with damp is dismantled and inspected first , then place a high-power incandescent bulb inside the gear motor for baking, or place the gear motor in a baking room for drying. This method is easy to operate , safe and reliable, but it is only suitable for miniature gear motor that is easy to dismantle and inspect. Special attention should be paid to the fact that the bulbs or heat source should not be too close to the coils when adopting the method , to prevent the coils from burnt out. Canvas and other articles can be covered on the shell of the gear motor for heat preservation.