"I report that GOKO decree #3774s issued on July 20th, 1943, instructed the People's Commissariat of Electronics Production to produce, insall, and test a KV tank with equipment designed by the academy and the NKEP by October 1st, 1943, and the GBTU was instructed to perform proving grounds trials by October 25th, 1943.
Production of the electric transmission was delayed, as a result of which the NKEP only presented the GBTU with the tank in November of 1944.
The tank travelled 267 km during tests. In the process of trials it was established that:
- The tank is simple and easy to drive.
- The tank turns well with variable radii and automatically compensates for different resistance to movement.
- The tank diesel engine works more stably and constantly when driving conditions change than with a mechanical transmission.
- Fuel expenditure recorded during the trials was less than the norm for heavy tanks with a mechanical transmission.
- Compared to the German Ferdinand SPG, the KV tank with an electric transmission has smaller electric motors due to raising the maximum speed to 5000 RPM.However, it proved impossible to test the reliability of the motors.
The electric transmission of the KV tank has significant drawbacks.
- The electric equipment is bulky and has many high current contacts. If even one contact is lost the tank becomes uncontrollable or stops.
- The components of the electric transmission are insufficiently protected against water, dust, and moisture that enter the tank.
- The ventilation and cooling systems of the mechanical transmission do not work when the electric transmission is installed.
The presence of these defects is explained by the fact that the electric transmission of the KV tank is the first experimental design in the USSR. It could not possibly be polished. The designers also had to work with the existing hull of the KV tank, designed to house a mechanical transmission.
The commission that studied the KV tank with an electric transmission came to the following conclusions:
- Cease further trials, as resolution of the multiple defects discovered during the trials will only cost time and will not radically improve the function of the components.
- Transfer the KV tank with an electric transmission to the Dynamo factory and Armoured Force Military Academy to continue the study of the electric transmission.
- Produce a test batch of tanks with electric transmissions without the aforementioned defects.
I agree with the conclusions of the commission regarding transferring the tank to the Dynamo factory and Armoured Force Military Academy.
Since the group of workers from the Armoured Force Military Academy and NKEP Dynamo factory who designed the experimental prototype gained valuable experience in this field and the development of electric transmissions for heavy tanks is promising, I ask you to:
- Task the Dynamo factory and Armoured Force Military Academy with developing a new electric transmission project.
- Task the Kirov factory with producing two tanks with electric transmissions that do not have the drawbacks discovered during the testing of the KV tank with an electric transmission.
We attach a draft GOKO decree and ask for its approval.
Deputy Commander of the Armoured and Motorized Forces, Colonel General of the Tank Forces, Korobkov
Member of the Armoured and Motorized Forces Military Council, Colonel General of the Tank Forces, Biryukov"
CAMD RF F. 38 Op.11355 D.2732 L.8, 9, 9 reverse
Printed in Glavnoye Bronetankovoye Upravleniye Lyudi, Sobytiya, Fakty v dokumentakh, 1944-1945 p.360