1. Preparation of ingredients
1.1 The casting mold should be preheated in the oven at 100-110 ° C
for more than 10 hours, and above 4000kva transformer coil
shall be given a longer preheating time,
To ensure that the coil is completely dry and its temperature is
not less than 80 ° C when installed.
1.2 The silica powder shall be sealed to normal temperature for
more than 6 hours in an oven at 110-120 ° C.
2. Ingredients
2.1 Static mixture degassing
2.1.1 Premixing
Material A (epoxy) is based on weight ratio, resin: filler: color
paste 100:(125-color paste amount):proper amount, and mixed
separately after adding resin, filler and color paste,
The temperature is 65-70 ℃, stirring and degassing for no less than
2 hours, and 100 < p < 200pa.
Material B (curing agent) is based on the weight ratio, curing
agent: filler 100:125, mixed separately, temperature is 65-70 ℃,
stirring and degassing are not less than 2 hours, 100 < p <
200pa.
2.1.2 Final mixing
Then the components A and B are finally mixed, the accelerator
agent is not needed, and put material A and B are mixed in the
proportion of 100:100 into (or vacuum suction) final mixing tank,
and in order to stir well, we advise put the resin and hardener
at same or alternate time
2.1.3 Start stirring after feeding,make sure the the spiral lifter
can lift the mixture onto the umbrella degassing hood at its
rotate speed
2.1.4 After stirring for 15 minutes, start the vacuum pump for
degassing. The vacuum degree shall not be less than 300pa
2.1.5 The mixing degassing time is about 15-30 minutes, and the
degassing is completed when there is no bubble on the umbrella
surface
3. Casting
3.1 Set the casting tank temperature at 80-85 ℃, preheating shall
start 4-5 hours before batching, and to ensure that the
temperature of the mold during installation is not less than 80 ° C
3.2 After batching, the dried and preheated mold is pushed into the
casting tank for vacuum treatment
3.3 The space temperature of the casting tank is 80-85 ° C, the
vacuum degree is not less than 300pa, and the vacuum treatment
time is not less than 2 hours
3.4 , The feeding should not be too fast during casting. It can be
stopped for 10-15 minutes, and the vacuum can be continued for
20-30 minutes after the material is full. If possible, it can be
pressurized by 0.2-0.3mpa after vacuum treatment
3.5 The final mixing casting shall be completed within 90 minutes.
Please strictly control the temperature and time to prevent
tank solidification. The excess single component resin and curing
agent can be stored for several days, but it must be sealed and
the temperature should be well controlled
