I'm confused with the output torque, torque developed in the armature

detski

1. The problem statement, all variables and given/known data
The armature winding of a 200 volt, 4-pole series motor is lap connected. There are 280 slots and each slot has 4 conductors. The current is 4 amperes and the flux per pole is 18 mWb. The field resistance 0.3 ohm and the armature resistance is 0.5 ohm. The iron and friction losses amount to 800 watts. Find: a. Output torque, b.) torque developed in the armature. and c) the lost torque


2. Relevant equations



3. The attempt at a solution
This is my attempt.
since it is lap= the number of parallel paths is 4
and the number of conductors= 280 * 4= 1120 conductors

Ec=200-4(.5+.3)= 196.8 v
196.8=(18m*4*N*1120)/(60*4)
N= 585.71

(196.8*4)=(2*pi*585.71*Tarmature)/60
Tarmature=12.83N-M

Pin @full load= (200)(4)=800
Pfield= (4^2)(.3)=4.8
Parmature=(4^2)(.5)=8

Pout=800-4.8-8-800
Pout= -12.8 w (There is no negative power right?)

-12.8=(2*pi*585.71*Tout)/60
Tout=-0.2087 Nm
Tlost=Tarm-Tout
Tlost=13.04 Nm

so... am i stupid or what